This girl used to behave like a girlfriend with me, as if she likes me. So eventually I also started liking her, now when I confessed my feelings for her, she said she sees me as a great friend. So was just wondering.
This is actually a psychological problem some people have. They want something they can't get, and want to feel like the Person they adore do them a favor when they get together. But if someone says that he likes the person with that problem, it means this Person can get him easily, and thats why they lose interest. This can be caused by many things: traumas from a terrible childhood, a hard rejection like a loud and terrible laugh when he/she asked someone out.. etc
Well it depends. If i had the same feelings I would be like cool lets get to know each other. If i wasn't interested in him i wouldn't see how i would of lost interest in him, when in the start there was nothing there in the first place.
Personally it hasn't happened with me, but i imagine if someone loses interest after you tell them you like them , it's because they don't feel the same way. So instead of being honest with you, they back off and become more distant towards you