There's no way to guarantee that he'll say yes if you ask. So if you don't want to hear "No" then you've kind of answered your own question.
Instead of trying to decide if you should ask him out, maybe you should spend time becoming becoming better / closer friends first.
Maybe try not to focus on the "ask him out" approach and instead try to organise things so that you spend more time together - but not on "official date" type stuff.
Like (for instance) why not try to organise for a small (mixed) group of friends to meet up just to hang around together and chat - it could be at the local park for the afternoon, or to see a movie (one that he will definitely want to go to see of course - even if you don't really care one way or the other about the movie), or to watch some kind of local sports or music event....
What I mean is that if you start going out with him AND a group of friends, then it might be easier to be able to casually ask him if he wants to see another movie with you and it could be interpreted just as a friend asking without the embarassment of an "official date".
If you manage to do that several times and you're still getting along well with each other, it might make it easier to ask him out (or you might realise that you don't want to date him after all
)