Trust is so important. First you must give a bit of it "for free" at the beginning and the rest comes only with time and facts.
I have also made some small jobs for people here and always found nice, correct, collaborative persons. If I can't finish them because I underestimated the effort, no money, that's fair. If I do it and it is what was expected, I get the money. Also fair
Luckily, only good experiences up to now