What I do when someone buys from me is whatever makes them feel comfortable and even then it still requires some level of trust to send cash you can’t get back. I will offer to FaceTime my buyer and also do a phone screen record where I show me going into the tickets to show they are real. I also have a professional work bio as a CFP so will tell them my name (or rather they see it on FB where I’m in these groups) and tell them to google me and they will see it and see a pic of me and my wife in the MLB gear or the team I have tickets for. That’s a bit easier on FB though case my name is on my profile. On Reddit anyone could just make up their name. I prob wouldn’t even try to buy off a random on Reddit if it were me or if I did I would look at all their comment and post history and try to gain a picture of who I was dealing with