英语语法：160 Assure Versus Ensure Versus Insure

Reader Christine wrote in with a request:

"I'd like to know the difference between the words insure and ensure, as in I-N-S-U-R-E and E-N-S-U-R-E. When writing, I often find myself backspacing so I can replace the word ensure with make certain and not feel like I've gotten it wrong. Thanks."
The Difference Between "Insure," "Ensure," and "Assure"
Guest writer Charles Carson answers,

The verbs insure, with an I, and ensure, with an E, derive¹ from the Latin word securus, meaning "safe" or "secure," which itself derives² from se, meaning "without," and caru, meaning "care"—literally "without cares or worries." Also derived³ from securus are the English words sure, assure, secure, and security. On its path from Latin through French and into English, securus became simplified and took on a variety of prefixes⁴, thus leading to the confusingly similar English verbs assure, ensure, and insure.

The verbs assure, ensure, and insure all have the general meaning "to make sure," and even though some argue that they are interchangeable (1,2), many maintain that their usage is dependent on context (3,4,5,6):
Assure is something you do to a person, a group of people, or an animal to remove doubt or anxiety, as in Squiggly assured Aardvark that he'd come to the party early. You can remember that assure can only be used with things that are alive (and both assure and alive start with a). Only things that are alive can feel doubt or anxiety, so only they can be assured.

Ensure is something you do to guarantee an event or condition, as in To ensure there'd be enough food, Aardvark ordered twice as much food as last year. You can remember that guarantee has those two e's on the end to help you remember that to ensure (with an e) is to guarantee something.

Insure can be done to a person, place, or thing, but it's reserved for limiting financial liability, most commonly by obtaining an insurance policy, as in Aardvark wondered if the caterers were insured against loss. You can remember that we take out insurance to protect our income if we become unemployed⁵, disabled, or injured in an accident. Both insure and income begin with -in.
Finally, the related verb secure is used when you take possession of a thing or place, as in Aardvark secured a beautiful hall for his party, or when you make something stable or safe, as in Aardvark secured the welcome banner to the wall.
Quick and Dirty "Ensure," "Assure," Insure" Tip
So the quick and dirty tip is to use assure for things that are alive (remember that a is for alive), ensure to guarantee events and conditions (remember those two e's at the end of guarantee), secure for things and places, and insure for all of the above in financial contexts (remember the i is for income).
What About "Reassure⁶"?
But wait, there's more. English has added its own prefixes to generate new words. The verb reassure is largely used interchangeably with assure, but it should be reserved for situations in which the assurance is repeated or ongoing⁷. Reassure can also be used when a previously⁸ held belief is later doubted—that is, a person who was once sure of something can be reassured⁹ if they later experience doubt. For example, one might say Tom's faith in the justice system was tested by the proceedings¹⁰, but the judge's final decision reassured him.
How About "Assurance," "Reassurance¹¹," and "Insurance"?
Then there are the noun forms. Assurance, reassurance, and insurance follow the same rules as their verb counterparts; use assurance and reassurance when eliminating doubt or anxiety in things that are alive, and use insurance (with an i) in financial contexts.* Unfortunately, there is no word ensurance (with an e), so writers must work around it with phrases like attempts to ensure, as in Despite Aardvark's attempts to ensure there'd be food for everyone, he forgot that Squiggly doesn't eat bugs¹².†

Administrative¹³

Thanks to Charles Carson, managing editor of the journal American Speech, for guest-writing this episode; and thanks, Christine, for your question.

NOTES

*Although usually used only for formal policies underwriting financial risk, insurance is sometimes used euphemistically in criminal situations involving money, such as cases of bribery¹⁴ or extortion, as in It was suggested by the neighborhood gang that the shopkeeper take out insurance to keep his store safe. In this example, the gang members are extorting¹⁵ money from the shopkeeper by threatening to damage the store themselves if he doesn't give them money.

†There are a few slang and specialized¹⁶ contexts in which assurance and insurance are used where we might expect to find the nonexistent ensurance. For example, insurance is sometimes used figuratively in non-financial criminal contexts, as in The drug kingpin kidnapped the witness's sister as insurance against further harmful testimony¹⁷; assurance is sometimes used by engineers and architects, as in The architect's design included some assurances against potential damage due to high winds. Here kidnapping the witness's relative and added safety features are intended to ensure a desired result (though one might argue that the latter example is actually the traditional use of assurance, with the building's owners or the public in general being implied as the ones being assured).

 

1 derive   

v.取得；导出；引申；来自；源自；出自

参考例句：

• We derive our sustenance from the land.我们从土地获取食物。
• We shall derive much benefit from reading good novels.我们将从优秀小说中获得很大好处。

2 derives   

v.得到( derive的第三人称单数 )；（从…中）得到获得；源于；（从…中）提取

参考例句：

• English derives in the main from the common Germanic stock. 英语主要源于日耳曼语系。 来自《简明英汉词典》
• He derives his income from freelance work. 他以自由职业获取收入。 来自《简明英汉词典》

3 derived   

vi.起源；由来；衍生；导出v.得到( derive的过去式和过去分词 )；（从…中）得到获得；源于；（从…中）提取

参考例句：

• Many English words are derived from Latin and Greek. 英语很多词源出于拉丁文和希腊文。 来自《简明英汉词典》
• He derived his enthusiasm for literature from his father. 他对文学的爱好是受他父亲的影响。 来自《简明英汉词典》

4 prefixes   

n.前缀( prefix的名词复数 )；人名前的称谓；前置代号（置于前面的单词或字母、数字）

参考例句：

• The prefixes cis and trans are frequently applied to disubstituted cycloalkanes. 词头顺和反常用于双取代的环烷烃。 来自辞典例句
• Why do you use so many prefixes while talking? 你说起话来，怎么这么多中缀？ 来自互联网

5 unemployed   

adj.失业的，没有工作的；未动用的，闲置的

参考例句：

• There are now over four million unemployed workers in this country.这个国家现有四百万失业人员。
• The unemployed hunger for jobs.失业者渴望得到工作。

6 reassure   

v.使放心，使消除疑虑

参考例句：

• This seemed to reassure him and he continued more confidently.这似乎使他放心一点，于是他更有信心地继续说了下去。
• The airline tried to reassure the customers that the planes were safe.航空公司尽力让乘客相信飞机是安全的。

7 ongoing   

adj.进行中的，前进的

参考例句：

• The problem is ongoing.这个问题尚未解决。
• The issues raised in the report relate directly to Age Concern's ongoing work in this area.报告中提出的问题与“关心老人”组织在这方面正在做的工作有直接的关系。

8 previously   

adv.以前，先前（地）

参考例句：

• The bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。
• Let me digress for a moment and explain what had happened previously.让我岔开一会儿，解释原先发生了什么。

9 reassured   

adj.使消除疑虑的；使放心的v.再保证，恢复信心( reassure的过去式和过去分词)

参考例句：

• The captain's confidence during the storm reassured the passengers. 在风暴中船长的信念使旅客们恢复了信心。 来自《现代英汉综合大词典》
• The doctor reassured the old lady. 医生叫那位老妇人放心。 来自《简明英汉词典》

10 proceedings   

n.进程，过程，议程；诉讼(程序)；公报

参考例句：

• He was released on bail pending committal proceedings. 他交保获释正在候审。
• to initiate legal proceedings against sb 对某人提起诉讼

11 reassurance   

n.使放心，使消除疑虑

参考例句：

• He drew reassurance from the enthusiastic applause.热烈的掌声使他获得了信心。
• Reassurance is especially critical when it comes to military activities.消除疑虑在军事活动方面尤为关键。

12 bugs   

adj.疯狂的，发疯的n.窃听器( bug的名词复数 )；病菌；虫子；[计算机]（制作软件程序所产生的意料不到的）错误

参考例句：

• All programs have bugs and need endless refinement. 所有的程序都有漏洞，都需要不断改进。 来自《简明英汉词典》
• The sacks of rice were swarming with bugs. 一袋袋的米里长满了虫子。 来自《简明英汉词典》

13 administrative   

adj.行政的，管理的

参考例句：

• The administrative burden must be lifted from local government.必须解除地方政府的行政负担。
• He regarded all these administrative details as beneath his notice.他认为行政管理上的这些琐事都不值一顾。

14 bribery   

n.贿络行为，行贿，受贿

参考例句：

• FBI found out that the senator committed bribery.美国联邦调查局查明这个参议员有受贿行为。
• He was charged with bribery.他被指控受贿。

15 extorting   

v.敲诈( extort的现在分词 )；曲解

参考例句：

• Corrupt government officials were extorting money from him. 腐败的政府官员向他敲诈钱财。 来自辞典例句
• He's been charged with extorting protection money from the shopkeepers. 他被指控对店主敲诈勒索保护费。 来自互联网

16 specialized   

adj.专门的，专业化的

参考例句：

• There are many specialized agencies in the United Nations.联合国有许多专门机构。
• These tools are very specialized.这些是专用工具。

17 testimony   

n.证词；见证，证明

参考例句：

• The testimony given by him is dubious.他所作的证据是可疑的。
• He was called in to bear testimony to what the police officer said.他被传入为警官所说的话作证。