You won't regret it

We use this expression to say that someone will benefit from trusting us or our opinions. It is common after asking for a favour.

我们用这个表达来说明某人会因为相信我们或我们的观点而受益。尤其会在当你请人帮忙之后使用这个句子。

For example, the other day somebody was trying to sell me a vacuum /'vækjʊəm/ cleaner and I said

举个例子，前几天有个人想卖给我个吸尘器，我说：

"Why should I buy it?"

我为什么要买这个?

and he said

他回答道：

"If you buy it, you won't regret it. Your house will be clean forever."

如果你买了它，你不会后悔的。你的房子将会一直一尘不染。