Ways to suicide

I’ve decided that I finally wanna end this misery. But I’m extremely scared of two things. A failed suicide attempt and that I might be suffering painfully (physically) before finally dying.
So I tried google and searched for painless and (almost) 100% success rate ways to suicide. But I can’t find anything. Google seems to have extremely strict filters anything related to suicide. How do I get more neutral and rational advice about painless suicide? I really want to be sure I’m gonna die and it would be fast when I do it.