offer a humble and sincere apology 负荆请罪

“负荆请罪”，字面意思是背着荆杖，向当事人请罪（proffer a birch and ask for punishment by flogging），用于赔礼道歉的场合，形容主动向人认错、道歉，自请责罚。可以翻译为“offer a humble and sincere apology”。

例句：

你最好是负荆请罪，我相信他会原谅你。

You'd better go and make amends to him. I'm sure he'll forgive you.