Well, what you do is get other books on similar subjects...tell her you have to do a study on it for a report or the tell the truth, morbid curiosity. Can she recommend any books with stats for example. I have worked in a library part time and I would feel some concern if I happen to notice what a person has checked out. Now our library, state of the art, lets you check your own books out. , The persons demeanor is what I go by. If you are even slightly thinking about it yourself, please remember one thing, in life everything changes from day to day, no matter whats going on in our lives, it can and will change, we have to decide if it will be for the better. If depression sets in, and doesn't go away, you gotta get help.
Years and years ago, a co-worker and I used to talk about writing a book on 101 ways to kill yourself, we talked about it in fun, made up all kinds of stuff. Cracked ourselves up. At the time I didn't realize she had some serious issues and was on medications, we transferred to different departments in different close by cities, same company. I cared very much for her, she had turned away from family years ago even changed her name. and we ,my family,became like a little family to her. I saw her as often as I could, she had moved less than an hour away. One time I didn't see her for like 2 months, she was in a relationship that I wasn't working out. I was going thru a divorce. She didn't call me. Imagine how I felt when she used our method number 3.