Your character is immortal. I don't know if you noticed but all they have to do is talk to the spirit healer and BAM new body. Or they could just walk to their old body and reanimate their corpse.
Evidence abounds that in the World of Warcraft, people have souls. If the person dies and doesn't become a member of the undead/have their soul eaten by demons, there are likely few possibilities as to what happens to the soul after death. I suspect that means that there's either some form of afterlife or a cycle of reincarnation.