What do you think about me not taking back a best friend who tried to get with my gf?
I think you're right for not trusting him. Do you have a reason to take him back?
Yes, my girlfriend doesn't want me to hang out with him anymore and I think I should take her side.
A best friend is not expected to hit on your girlfriend because it is very wrong and rude. Thus it is okay then to stop being friends with them when they tried to get with your girlfriend.
Oh, you are right. I should take her side in this.
Any friend that tries to get with your girlfriend behind your back is no friend at all. It would be best to let go of that friendship if you can't trust him.