I don't have all the answers, but this is how I cope with my spaget>strangers smile/are nice
smile and be nice back but carry a knife/mace >guy likes you, but you don't like him
polite but firm decline that extinguishes all hope without making him look stupid in front of friends. I like the "emotionally unavailable" excuse. If all else fails , carry a knife/mace.
I'm still super autistic when it comes to any situation that can't be solved with being polite and carrying a knife/mace