愧疚

nèi xīn gǎn dào kuì jiù

内心感到愧疚

feel a deep sense of shame and remorse

kuì jiù zhī xīn

愧疚之心

feeling of shame and remorse

tā wàn bān kuì jiù xīn rú dāo gē

他万般愧疚，心如刀割。

He was pierced to the heart with guilt.