2 week trials aren't long enough in my opinion, like Scott said, I'd rather go on a hunt with this dog and the pack and handler he's used to and buy him outright before I'd take one on a trial. Then probably expect about a month (4-5 hunts if you hunt on weekends only) of the dog staying at your feet.
They are unsure and don't trust you yet, they want to know if they are gonna go out and hunt for you, are you gonna return the favor and find them or wait for them to come back?
I have had more success buying dogs that I have hunted behind, but are "not for sale" which usually means I really don't want to sell this dog, but if you put enough bills in front of me, I will sell the dog
I wish I had the money to do that, lol