James Frain is an obsessive vampire who can't believe his kidnap victim is afraid of him.  This is played kind of for laughs, and I've never liked how "True Blood" vampires cry "blood", thus making it very difficult to tell if an actor is crying real tears, but Frain really goes for it here.  
He also has an excellent serious crying scene in "The Tudors" (season 3, episode 8, "The Undoing of Cromwell"), which I can not find anywhere on the internet to provide a link for.  His Thomas Cromwell makes his final remarks to a jeering crowd as he faces execution.  He is heartbreaking.