How do I know if he is serious about me?

I have a bit of a complicated love situation… try to keep up ;)

Well there is a guy and I really like him, I’ve liked him for a while actually, 3 years to be exact. But I’ve heard from multiple friends (who to my disdain have dated him). that say he ‘goes after everything with a skirt’ and at first I didnt mind so much, I mean harmless flirting is okay right? But thats when I saw him beeing really… flirtaitous around other girls. I’ve had a few boyfriends myself but none of them bring out that same attraction as he does, so I figured that he doesnt HAVE to like me right now and he probably doesnt feel the same way. I painfuly decided it was enough to just be around him. But after a while it wasnt enough anymore, I wanted him to be with me and so I told him how I feel, he told me he felt the same way, I was kinda an idoot to think that we would all of a sudden get together. But it was the best thing I could have been told at the moment, the worst was that he was moving (he is older than me so were in different schools but they are right next to eachother and he is kind of a drop out) but he promised that he would come and see me every day after school. a few days later he got kicked out of the house and didnt have a phone so I anxiously waited just to be able to see him when school started up again… schools been going on for a few weeks now and I havent seen him at all.. is he serious about me or is he just messing around with my feelings?