Should I be honest in how I feel about my teammate?
How do you plan to be honest with your teammate?
I wanted to write an apology letter to him
The more honest you are, the more easy it is to trust. Not only will others trust you, but you can also feel more confident when trusting others.
I appreciate your advice, I am going to talk to him.
I'm happy to be of help. Your friend will admire your honesty and you two can become even closer teammates through such truthful communication.