Sometimes it takes time and people on the circle of your trust to get that green trust though. You can check this general board of
Marketplace, it's where you can gain this trust if you're into p2p trades and escrow but it isn't limited in here because you can gain trust on other boards as well, for example, your local board if you want to start your service/s there.
Well I understand your point, but those
circle were leave positive trust isn't correct if it's because the user is nice to you and not from risking a money. Also you're like teaching him how to farm positive trust and make him looks trust-able, while it doesn't good.
@OP you don't have any reputation yet, anyone wouldn't use your escrow service. Better to offer another services (e.g. design, lending, etc) and be professional, don't need to think how to gain trust because it's subjective similar as merit.