抱愧

zài nǐ kùn nan de shí hou méi néng jìn lì wǒ shí zài bào kuì

在你困难的时候没能尽力，我实在抱愧。

I feel ashamed of myself at being unable to help you out at this difficult time.

bào kuì chéng rèn cuò wù

抱愧承认错误

blush at one's mistake