'Verzeih mir' or 'Vergib mir?'?

For context, this is for a book and the character speaking is very, very old and poetic by nature. He's speaking to someone he loves who he harmed severely a long time ago through actions he now regrets.

Danke, Katatafisch! To answer your question, it's because German is his native language, and he tends to lapse into it when he's upset. It's actually in a transitional period between the loved one dismissing everything as "he said something in German I couldn't understand" and direct translations as the main character picks up the language over the years. In the middle period, the main character hears it in German first before translating it.

But even later, as I'm trying to learn the language myself, I am trying to translate much of the conversations to the best of my beginning student ability even if the German won't make it to the book. Partly for practice, partly to try to keep from using words that have no actual translation/equivalent.