This is book 6 is the Argeneau Vampire Series and I loved it.

Lucian Argeneau, who is uncle to the people in the earlier books, is a hunter of rogue vampires and he has come to Kansas City to hunt one when he finds Leigh, a recently turned vampire.

Lucian has been alone for a long time, since his family was lost in the fall of Atlantis. He is left with having to look after Leigh and help her through her turning - he also finds he cannot read her which means she could be his life mate. Both Lucian and Leigh have to come to terms with that one.