I have known my best friend for more than a decade. Once last year, he confessed that he has feelings for me. I kind of guessed it quite some time ago but I thought it would be better to tackle it when he finally did confess. I told him that I didn't have any romantic feelings for him, but I would like to continue being his best friend. Then later he told me that he only pretended to confess to see how I would react, which I knew was just a cover to hide the fact that he was hurt. In fact he has done the same thing several times before when we were in school. Each time I had clearly told him that I was not romantically interested in him. Now, the problem is that he is very persistent to the point that sometimes I feel pissed off. Sometimes he says that he loves hugging me, sometimes he says that he wishes he could kiss me. And he constantly flirts with me. I just can't take it anymore. How can I tell him once and for all that I don't want to be his girlfriend?
My second problem: when he has a problem, I do my very best to listen to him and be supportive. When I have a problem, I talk to him and I get the feeling that he always tries to 'top' my story. And in the end, we end up listening to him. The he would tell me that he wasn't trying to top my story or make it seem like his life is worse than mine. All I need my best friend to do is to listen. Is that too much to ask?
My third problem: he has always been pushy. If he tells me that he misses me or loves me, he demands to hear the same thing from me. How can I tell him that I'll say that I miss him on my own accord?
Help!

Well, you don't say how old you are, but it sounds like you are making the transition from childhood to young adulthood. It's a painful truth that not all friendships survive the transition, especially boy-girl friendships. Your friend is being pushy, presumptuous and selfish and you need to be very firm to make him understand that you don't appreciate it and won't tolerate it, even if it means the end of your friendship. Pushy people tend to take advantage of other people's kindness and tolerance to get what they want. Don't let him make you feel guilty for saying NO. You are completely within your rights to insist that he respect you by keeping a distance that you feel comfortable with.

You've both changed and he wants more from you than you are willing to give. Now that you know how he feels, leave him alone and don't give him any reason to think he has a chance with you. He is not your best friend anymore. Sorry.

You have both out grown the friendship. He is looking for more. And I have to say that the persistent bit makes me feel uncomfortable. Distance yourself from him for a while. Give him time to sort out his own feelings. If he continues to persist in pursuing you in a romantic way, you might need to explain that it is making you feel 'pissed off'/uncomfortable and that he MUST STOP. Be firm. Avoid letting him think you are just playing games or flirting. He needs to know you are serious.

I don't get it. One of the beautiful things about a best friend is that you are supposed to be able to tell them EXACTLY how you feel, what you think and why you think it. If he is in deed your best friend, then you need to tell him what you just posted to us. If he see's your honesty, that may draw more sincerity out of him. Tell him that you need him to be your friend and listen. This means that even if he has a problem too, he should be considerate and listen and help you with yours. Then, he can address his own situation afterwards.

my second problem: when he has a problem, i do my very best to listen to him and be supportive. when i have a problem, i talk to him and i get the feeling that he always tries to 'top' my story. and in the end, we end up listening to him. the he would tell me that he wasn't trying to top my story or make it seem like his life is worse than mine. all i need my best friend to do is to listen. is that too much to ask?

This is pretty common... it's just a difference in the way people handle problems: Guys tend to be more likely to say "That sucks, kinda like when I...", because it's usually much more likely that we're just griping about it in general rather than looking for solutions. We're not trying to top the story (well, maybe just a little, in that always-competitive way that we are, but that's not the point of the thing), just letting you know that yeah, we've been there and we understand. Girls are more likely to go into solving the problem. It causes friction both ways, because if that's the approach we take when responding to an issue, that's also probably what we're looking for when we bring up an issue.