She must have misheard.

她一定是听错了。

I thought he said he was coming today, but I must have misheard.

我以为他说他今天来，不过我一定是听错了。

You misheard me, Frank.

弗兰克，你听错了。

You may have misheard her—I'm sure she didn't mean that.

你可能听错她的话了—我肯定她不是这个意思。

Gee Woo: I guess I misheard?

智宇：我想我听错了？