So I'm in high school now and I like this guy and we kissed today but then people started telling that he is desprite and that he has things with a whole bunch of girls and there's this girl that he is always with and it seems like he really likes her so I don't know why he likes me?? What should I do

Ask him.

It sounds like he isn't interested in a relationship (because of all the girls he's supposedly "has things with") and if a relationship is what you want with him, talk about it.

It sounds to me by the way you said "im in high school now" that you're rather young. I wouldn't stress about him. There will be plenty of other guys out there that.

Don't go after the guy that wants you to be part of his world, rather cling to the guy who wants you to BE his world

I think you should ask him, but if you don't want to do that, playing him hot and cold is a good move. It sounds like this guy is like a trophy collector - he just wants to add you to his collection. If he feels the trophy is walking out of the cabinet he'll work harder to keep you and you'll seem more attractive to him.
Alternatively, you could just wait for someone you're certain about to come along and ditch this guy. If you've just started high school there's no rush.

Hope this helps xx