my lips are sealed

We use this expression to say that you won't tell anyone a secret.

我们用这个短语来表示我们不会轻易把秘密泄露出去。

A: Did you get a pay rise last month like the rest of us?

上个月你和我们一样都加薪了吗?

B: I'm sorry, I'm not supposed to discuss my salary with anybody else.

对不起，我不应该和别人讨论我的工资。

A: But you know I wouldn't tell anybody. Honestly, my lips are sealed.

但你知道我不会告诉任何人的。老实说，我守口如瓶。