Should I tell her our date was a bet?

My friend and I recently had a bet that involved going on a date with a girl we both know and trying to get her to agree to a second date. She didn’t like him, but asked me out, and I don’t know what to do because I have no interest in her. I only did this as a stupid dare and because it made me happy to win the bet and make my friend feel foolish. I feel a little guilty because I don’t want to play with this girl’s emotions, and I am thinking of just telling her the truth. My friend says this is a bad idea because if she tells other people about our bet, we will end up with bad reputations. I don’t know what to do. Should I go on a second date with her and tell her I am not interested?
You and your friend need to take a good look at your priorities and evaluate your need for this sort of validation. Think about where you get these ideas from, why they are insulting to other people, and what you both hope to accomplish by spending time on acts like these. As for your guilt, there is no way around it because you know you did something wrong. If your friend is worried about his reputation, it may make sense to not do things that lead to a bad name. I suggest you meet her and be honest enough to tell her you’re not interested. At the very least, it should prevent you and your friend from doing something like this again.

Should I tell someone I like her even though I know she isn’t interested? I don’t know if it will make a difference, but I don’t want to regret not telling her how I feel if she changes her mind some day in the future.
If you know she isn’t interested, and are prepared to be disappointed, telling her what you want to is entirely up to you.