—You have a big mouth, Sarah. 莎拉，你真大嘴巴。
—Wait a minute! I didn't tell anyone... I swear! 什么，我没有告诉别人……真的！我发誓！
—Oh, give a break! 我不信！

You have a big mouth!=You said too much! 你的话太多了！

Wait a minute!=hold on 等等

Give a break=Give me a break/Oh, please! /I don't buy it./Cut the crap. 我根本不相信你的话。