He may have said “maybe” because you aren’t his first choice.
There may be someone else that he likes more than you.
He may be waiting to see if he can get this other person to go out with him.
You may have simply been someone that he was showing a lot of interest in so as to keep you as a potential dating option, if things don’t work out with this other person.
As of now, he may still be hoping that things work out with this other person.
By telling you “maybe,” he may be attempting to keep you hopeful while he continues trying to get the person that he really wants to go out with him.
If it doesn’t work out with this other person, that may be when he decides to take you up on your offer to go out.