why is it so funny

OK for every one who reads this tell my if you think its funny. When some one tells another person how they feel about they feel about, that person is it right if that other person laughs. Is that right. It Fucking pisses me off, it kills me when even I do it. Recently I told a girl how I felt about her and she laughed at me. She said " Please stop, it's boaring me." It killed me inside, and I hate it. I hate it so much, I might as well just fucking give up dateing period. Every time I go out with some one I get cheated on, or they dump me and go out with one of my friends. God some times I just want to kill myself because I relize that I will never be happy.