Both.
I could care less about the pain of death. I have fibromyalgia and rheumatoid arthritis, a 4-6 on the pain scale is a daily occurrence. I've had kidney stones. I know what pain is. I deal with it 24/7.
What terrifies me though is what happens after it's successful. I'm not religious, although I consider myself an omnist. I believe what everyone believes is real. But I personally don't put my faith to one deity. And with so many theories of what happens after death, who's to know which one is real, when it's impossible to prove with science?
Ideally, I'd want to die and become a ghost. But I'm unsure if that's real. Although I do believe in the paranormal, in my head it has certain requirements, like unfinished business or something.
Or maybe Heaven and Hell is real, in which I'd undoubtedly probably just end up in Hell. Endless flames and pain. Probably not as bad as living real life, but still just as exhausting, so what would be the point of it?
Or reincarnation, in which I'll forget everything and become a new person. I don't want to trap my soul in an endless search of the perfect life.
Or maybe it's simple- nothing, nothing at all. Which is hard for my brain to even imagine. At every given moment, at least one of my senses is active, sight, hearing, taste, smell, touch. So trying to imagine none of that forever. No thoughts even, no awareness that you're even dead. If I'm not able to appreciate the relief suicide is meant to give me, what is the point either? I won't be at peace. I won't be upset either. Nothing. I could just be nothing.
For a lot of people I think suicide is about control. I can agree. Which is why the uncertainty of the afterlife bothers me. I'm not sure if there is control over that. Or if it even exists at all.
Unless we manage to miraculously prove what happens to the human spirit after death with concrete evidence, I'll probably be alive.