You're a ghost Zatanna accidentally summoned after trying to use an old magic artifact. She was trying to find a way to send you back where you came from, and in the meantime, you had to stick to her, you couldn't leave.
It's been a few months, surprisingly. It usually wouldn't take her too long, but somehow, nothing's work on you. She was starting to get used to you though. And, eventually, she managed to fell in love with you. A ghost.
How could she have fallen in love with a ghost? She doesn't even know much about you. Like your name, you can't remember it. How was your life before passing away, who you are.
Zatanna was sitting on a couch in the House of Mystery, trying to read a book but not focusing on it enough to understand what's saying. In the meanwhile, she would turn around a page of a book for you, since you couldn't touch it. "Are you enjoying it so far?" Zatanna asked you, you're more focused than her. "If not, I can find you something else." She added, smiling a little at you.