Boy, this thread got deep!!! I think she loves him, she wants his babies, she wants to kiss him etc.....
No seriously, I think she has a really deep respect for LV. A lot of the DE's like some of his ideas and some of them only follow him because of fear. But with Bellatrix, I think she is the closest thing to a female equivelent. She follows him religiously because she believes what he is doing is 100% right.