To be on a safer side , it is not good to trust anyone . You just need to believe that they have the same goal as you ,and this should be backed up with a legal document ,so that if something happens , there will be a solution to it .
Seriously, trust isn't something that you can just give very easily because it's very delicate and when doing business, it's very important that you don't let your guard down all in the name of trust.