I don’t like her romantically and want nothing sexual with her either. She acts desperate to talk to me, won’t get into more details.
I could act busy each time she approaches me, and avoid her as much as I can but I don’t know if I should tell my manager about this. I don’t even know what I’d tell a manager: “I’m informing that I want nothing to do with X and I’m going to keep my conversations with her to a minimum”?
Another idea: be boring as f*ck.
Do I tell her friends I don’t like her?
Ideally I could tell her directly I’m not interested / I don’t befriend coworkers (not true but it would work to soften the blow), but I simply don’t know how defensive she’s gonna get, laugh it off or accuse me of playing games.
Raise it with your boss that she is making you feel uncomfortable and you’d prefer conversations were limited to work only. That is exactly how a woman would handle it if a man was being weird, and you have every and equal entitlement to be left alone.