I'm not certain. It will probably never be a certainty for me. I have been telling myself it is a certainty for about 16 years now and I still keep going. That's not to say that I didn't come close, of course. I suppose what stops me from making it an absolute certainty is that I probably have a high tolerance for suffering. I always have hope in some capacity, because I lowered my expectations to the point that I could probably continue existing with nothing but the clothes on my back. I have spent the majority of my adult life by myself and while that is cause enough to ctb, you kind of get used to it. It becomes a friend.
I'm facing another conundrum as I get older, in addition to my perpetual suffering. The longer I live, the more violent I feel and the more rotten my morality becomes. This flies in the face of a lot of my core values as a human being, so it's very distressing. This new problem is more of a solution really, which is to say that I should probably just do it before I hurt someone.