When Jason came back from the dead he didn’t really remember anything from before he died, that was the pits way it poisoned his mind. But the pit couldn’t take everything from him, he remembered a voice and a feeling. He remembered a woman, he remembered the love he felt for her. Then he began to go crazy with the thought of this faceless angel, the only thing he remembered from before he died. So the league let him go and he went onto Gotham to find this woman, and it wasn’t until a few weeks later that he heard that voice. Then when he saw the beautiful waitress the voice belonged to he couldn’t help but follow her, he wanted his angel safe from harm. So that’s how you ended up with a stalker who has been leaving notes at your job and apartment.