For instance, you could say, “I’m truly, truly sorry about what I did. "
As an example, you could say, “I know that when I made a joke at your expense I hurt your feelings. I should’ve thought before I spoke. I know you’re sensitive about that issue. "
As the end of the apology, you could say, “Next time, I’ll try to bite my tongue before I speak. You deserve better from me. I love and respect you, and I want to show you that with my actions. "
You can give him a space to talk by saying, “How do you feel about what I’ve said?”
One way you can show you’re listening is by repeating back what he’s said. That is, you can say, “What I hear you saying is that me making jokes like that makes you feel belittled and disrespected. I totally understand that, and you are totally valid in feeling that way. “[10] X Research source
That doesn’t mean you should completely forget about it. You should definitely use what you’ve learned to do better in the future.