What dose he mean by: "i can open up to you"?

Question

my two best friends are going out. i text the boy a lot because i miss him. he tell me about everything that is going on in his head, even about his girlfriend. i was shocked when he started talking to me like this. and one day he was like. " i don't know, i just really feel like i can open up to you." he wasn't being joking about it at all. i could tell. i just kinda want to know what you guys think he means

Answer 1

He feels like your relationship is close enough that he can tell you anything; which is fine, but geeze he might tell you stuff you really dont want to know about him and his girlfriend...be weary..

Answer 2

He can trust you to listen and maybe understand where he is coming form sometimes.

Basically in a nut shell, he can talk to you about anything