Conflict in Motive
The way he behaves sometimes scares her. He has the ability to transform from a normal looking guy into a monster with a bumpy forehead and sharp teeth - within seconds. It's not normal. It's not human.
She has told him that and been rewarded by more concern and apologetic words than he should really be giving her given that she is pointing out the obvious. He's a vampire. For him, the change from man to demonic being is normal. It's second nature.
But still, she feels a sense of anticipation every time they cross paths, and she wonders, will he turn evil tonight? Will he bite someone? Her? She can't help it. Call it human instinct. A part of her doesn't trust him. It can't.
She just doesn't trust what he is. For some reason, she does feel safe around him though. Other than the fact that he has not killed her and on a few occasions has saved her life, she has the belief that he will be there for her if need be. He won't harm her. He is there to protect her.
It's ridiculous to think that might actually be the case knowing that he is a vampire. Vampires drink blood. Vampires hunt humans. Vampires and humans are mortal enemies. Do the math. However you phrase the question, the answer will always be bloody and final. Death is the only possible ending.
Even disregarding the vampire thing, she can't think of any reason why she should trust him. He's a private investigator. He works by himself more or less, with just a few employees who don't quite seem like employee material hanging about. Little is on record about him. What there is on his employees doesn't raise too many questions.
There should be something more for her to go on, but there isn't. This is unlike her cases as a detective. Nothing comes close to the farfetched sounding stories that are Angel's life. Nothing will. No information and further research will help her.
Her instincts are all she has. And while usually she would trust them, they are concurrently screaming at her to run and to stay. Conflicting feelings. She doesn't know which voice to listen to.