Sorry Apologetic Repent Regret in Chinese / Japanese...

後悔 is the feeling of being or feeling repentant, apologetic, and regret.

後悔 is not sorrow.

This term is often used in the context of Buddhism and other religions.

Note: This is a strange thing to write on a wall scroll for Chinese, Japanese, and Korean people - but you can bend the rules if you want in the west.