I have a friend who got married 3 years ago,but now he's getting divorced,and he's afraid she's going to take half of the stuff he had bought before they get married! Can she do that?
Can he sell his trucks whenever he wants since he had them before they get married,and her name isn't on them??

Who are we talking about, you or your "friend"? :D

Yes, you can sell your truck. But your wife, in the event of a divorce, might claim some portion of the proceeds.

It's arguable that pre-marital property shouldn't be considered available for distribution in a divorce, but you never know.

It depends on the State that they are in. Laws vary widely. In states like California it would be separate in others it is not.