What are your ages?
Where do you know him from?
Do you call and talk to him?
Are you saying you like him?
First let me tell you, you can't ever know what another person is really thinking. You can only know what they tell you they are thinking. Whenever we fall in love, we take the chance that our hearts will get broken, thats just a fact of life.
It seems like he's given you every hint that he likes you and certainly wants to be more than just friends with you, so you have to decide if you want to move forward in this direction or if you want to keep it at just friends. His anger and rudeness could be because he feels like you rejected him and can't figure out why.
I would suggest talking to him and telling him that you were too scared to get involved because you value him so much as a friend that you didn't want to do anything to ruin that. Tell him that you would be willing to talk about it and maybe go on a date and see what happens from there. If he agrees then do just that, go on a date, spend some time together, do not rush into a relationship and certainly do not rush the intimacy. The longer you can hold off on a relationship commitment and intimacy the better chance you will have to get to know each other as potential mates rather than just friends.
I welcome your thoughts, let me know if you want to talk more
So...at this point, what is your question?
Its not unusual for a guy to use 'what if', its a way for him to know if you are interested without putting himself out there.
It's my pleasure. I'm glad I can help. At this point, I think you may have really hurt his feelings when you 'put him in his place' so to speak. Right now, you will have to change tactics and if you can't outright ask him how he feels or ask a friend to ask him how he feels then you will have to use the oldest language in the book....body language.
When he looks at you, give him a sweet smile and then look down or look away. Compliment him on something he wears, but in a casual manner....put your hand on your chin and say, almost as if you are surprised at the thought " hmm, that shirt looks really nice on you", and then just talk about something else like you never said it. When he said, 'sorry, I'm not taking you', you should have laughed and said, 'you know you want to take me' and smiled at him. Keep a sense of humor about it, and don't get mad at him being petty. Keep a smile and be sure to look at him from across the room. See if you have something he might like, a book, magazine, or something you know he likes and give it to him. "oh, i saw this and thought you might like it' and before he can say anything after you give it to him, change the subject. All of this will throw him off guard, but at the same time, if there was interest in you 'like that' then he will come around.
I'm here if you want to talk more