<human>: I've(25M) been in love with my friend(25F) for a while now but I haven't told her about my feelings as she is in a relationship. Every time we are out together we are flirty and it's really fun, but last time we was out she was going out of her way to make physical contact and she kept asking if I picked up when women are attracted to me. This made me want her even more as I felt she may be dropping hints. 

I don't want to ruin a friendship or a relationship unnecessarily but I can't stop thinking I need to make a move. How should I go about doing this, if at all? The fallout for a failed attempt would be our friends thinking I'm an idiot and douche but I'm willing to take the risk. My heart literally aches every time I say goodbye to her so some advice would be nice. Thanks in advance.

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<bot>: I'm in love with female friend who is in a relationship already, how can I tell her my feelings and try and win her over