As others have said, start your trading by making a few trades with long time members that YOU trust--as determined by their exemplary feedback. You can offer to ship first to demonstrate good faith on your part, and if they have lots of positive feedback you can be reasonably assured they will hold up their end once they receive your knife. Members with 100% positive feedback amassed over multiple years generally won't jeopardize it by doing something dumb.
Once everyone is satisfied, ask that they give you positive feedback. Repeat as necessary until you have accumulated enough positive feedback that others will feel comfortable dealing with you.
NRA Endowment Member
I don't own an assault weapon. I own a counter-assault weapon.