Con men use social skills to get close to and manipulate their victims. They are better at doing this than most people are at seeing through them. Gavin de Becker wrote an amazing book called: "The Gift Of Fear."
In it he identifies 6 strategies that criminals use which can be identified and used to boomerang back on them, whether they are after you wallet or your life.
Reading this is no substitute to reading the book. I wrote this to encourage folks to get it and read it diligently.
1. Forced Teaming - the false “WE” partnership. De Becker gives many examples of what this looks like but it boils down to phrases and attitude that imply that two strangers (one of which is you) have a lot in common and are sharing a moment, getting closer and trusting each other as it were.
Defence - Don’t buy in; make it clear you are not partners and never will be. Who invited him into your life anyway? Raise your voice, be firm, be rude if you want.
2. Charm and Niceness - Charm is what someone does, not what they are. Sincere charm is one social skill that all con men and a lot of street criminals share, but it is fake. They do not mean it and it is very hard to resist.
Defence - If someone is being nice out of the blue, ask, “Why is he being so nice?” Explicitly rebuff his approach with no ambiguous terms. “Go away! Leave me alone!” You may even be rude. If he really is nice, he will listen.