It usually works like this, people who stayed somewhere and were good guests will have more than one good review. I ususlly look for several reviews. No rewies no booking no matter how trustworthy they look and how nicely they tell a sory. You also know that the information like bank accounts and visa numbers are good because no body will go change visa every month or so.
One review is not enough, the more they have the better. Remeber NEVER trust anyone 100% Check ID to see if they are the right people, ALWAYS ask for deposit when booking. One guy took my towels, I had to request the money from his deposit. Keep you belongings secured, lock your room. No exception to the rule.
Its better to be safe than sorry. And even then you may be robbed so protect yourself.