How many times would you deal with someone like this?

I’ve sat up with a “friend” trying to convince them that life is worth living probably about 7 or 8 times since I’ve known them. At this point it’s really just getting annoying. I mean seriously, how many times do you have to listen to someone talk about killing themselves?
Do you think I’m wasting time with this? How many times would you try to comfort a friend like this? Is it bad that I don’t really want to talk to her anymore?

Edit: They claim to not have friends or anyone that cares about them. Should this make me angry, or sad, or how should I feel about this comment?