To get him to trust you again, avoid trying to do so in an obvious and very transparent way.
If you try too hard to get him to trust you again by continuously telling him that you can be trusted and to forgive you, you will only end up making him think otherwise.
After all, all words and no action provide very little evidence that you are indeed someone that he can trust again.
You need to use action instead of words.
If you have mutual friends with this guy, start helping those friends out in beneficial ways.
It may be with giving them good advice on particular problems that they may be having or actually helping them out physically with something that they need help with.
If you do this often enough, the word will get around about how great of a friend you are and he will hear about it.
This will make him feel inclined to ask questions about you to these mutual friends who keep singing your praises.
If he hears enough accounts about your helpful behavior, he may feel the need to reach out to you.
This is when you will have your second chance with this guy.
Be humble in your interaction with him. Don’t praise yourself.
The key to this working is in other people doing the praising and consistently speaking well of you.
In time, he may reach out to you more and more.
Eventually, the both of you could be right back into it.
This method requires time and patience on your end.
However, if you value this guy enough, it would be worth it to put in the time and effort required to get his trust back again.