痛改前非 ------------- thoroughly rectify his errors

例句：
A: Carl swore he would thoroughly rectify his errors.
卡尔发誓他要痛改前非。
B: Really? That's the way it should be.
真的吗？应该这样。

同义词：
sincerely mend one's ways

注释：
That's the way it should be. 应该这样。