生活英语手册 108（6.促进理解－6.12劝说、许诺与

　　我向你保证。
I promise you.
我向你保证我会保守秘密。
I promise you I'll keep it secret.
你可相信我。
You can trust me.
我会信守承诺的。
I'll keep my promise.
我说话算数。
I mean what I say.
他是个说话算数的人。
He is a man of his words.
我不会让你失望的。
I won't let you down.
我发誓。
I swear.
我不能保证。
I can't promise.
我不能向你许诺什么。
I can't promise you anything.
他们包退包换。
They guarantee the exchange or refund¹ of the goods.
我会尽我所能帮助你的。
I'll do all I can to help you.
答应了就要做到。
A promise is a promise.

1 refund   

v.退还，偿还；n.归还，偿还额，退款

参考例句：

• They demand a refund on unsatisfactory goods.他们对不满意的货品要求退款。
• We'll refund your money if you aren't satisfied.你若不满意，我们愿意退款给你。