心直口快 ----- frank and out-spoken

例句：
A: Betty is said to be a big month.
据说贝蒂说话爽快。
B: Correctly. She's often frank and out-spoken.
对的，她常常心直口快。

同义词：
What the heart thinks, the tongue speaks.
Nearest the heart, nearest the mouth.

注释：
a big mouth 说话爽快