I have always held out the possibility that she was sold.
I think his belief that Natalee is still alive is based on the fact that he doesn't believe anyone in Aruba would do such a thing. A friend of my wifes is going to Aruba tomorrow. They are from there. She has been talking with her family in Aruba and telling my wife what is going on. Everyone there is in a solid state of disbelief regarding the disappearance of this girl and can not imagine that she has been killed.