Please help, problem with guy/friend?

ok so I'm friends with this guy and I really like him. But the weird thing is that he always denies that we're friends, even though we talk all of the time and have a lot in common, someone will say, "Oh yeah you guys are friends, you can work together." and then he'll be like, "friends? yeah right" or something. I really don't know what to think cause i really really like him and i'm like fifty percent sure he likes me back but it's like he denies that we're closer than acquaintances. cause it's like he smiles at me a lot and when i talk to him it's like he's always looking into my eyes... and the other day on the bus someone was joking with me and they were like, "ewww... who would ever want to date (my name)... she's so ugly..." and then he was like, "actually, (my name)'s not..." but then it was like he sort of stopped himself. the other weird thing is that whenever we chat it's me who starts the conversation, but then he talks for a while and once he was like, "I have to go now, but I'm here if you need me XD." so what was that about? and it's like completely possible that he likes someone else (there are two other girls who i think he could like ban they're both really pretty...) We're both really good students and as I said before have a lot in common but no way could i ever be able to ask him out or ask him if he likes me cause i'm way too shy. No one knows that i like him but should i tell one of my friends so maybe could she ask some of his friends who he likes? cause we're all kind of in the same group of friends... I just really don't know what to do.