Money Moral Dilemma: Is it OK if I choose to sell something to a woman rather than a man?

Ringo90

I'm a woman and I've lived alone at times so I've been in this situation. Most of the times I've tried not to worry and trust the buyer but that's personal. When possibile, since I live in a block of flats, I don't give my apartment number to the buyer, wait for them to get at my building and send me a text, and then meet them in the hall of the building without taking them to my apartment. If you can, do something like that.

Diana2014

Your friend appears to have got it into their head that discriminating between a woman and a man applies even to personal transactions. Since you're not in the sales business, just disposing of something you own privately, that's not relevant.
The Equality Act framework doesn't apply in all contexts, just "at work, in education, as a consumer, when using public services, when buying or renting property or as a member or guest of a private club or association" - see Discrimination: your rights: Types of discrimination ('protected characteristics') - GOV.UK (www.gov.uk) .
You have every right to avoid having a potentially threatening person coming to your home and to take whatever precautions you feel necessary to prevent that.