The trust system and feedback on the person is not conclusive but that will serve as your best basis in order to determine if such user can be trusted. In addition, you can also consider their history and contribution in the forum as those may help you in determining their position in the forum.

Warning though, recently, there were trusted members on the forum who took advantage of their positive feedback and they decided to default on hefty amount of loans. Like what I mentioned, the trust system is not a conclusive evidence that can guarantee you a successful and safe transaction. So if you are dealing with large amounts of transactions in the forum, I highly advise for you to hire an escrow or a third-party that can hold such funds for the time being.