How do you know you could trust anyone claiming they're trying to help you ?
Sad truth of the matter is you shouldn't trust anyone.
Research them if you're feeling very ambitious.. the payment info they use.. the usernames & emails they provide.
I think the best thing though is avoid people that try to rush you.. they aren't worth dealing with either because they're dbags about it.. or trying to rush you through a scam so they can block you after they get their part.
Once you decide to make any sort of deal with someone you're pretty much hoping for the best.
People will probably tell you "only deal with trusted people" but not offer much advice on what that means to them since it's all relative.
Good luck.. it's a jungle out here.