How do I know? I was there and experienced it. There is no doubt. And that is a blessing.
As far as no good reason has convinced you God is real...well for me if I look around, the sky, nature, each other, the crazy details that can't be by chance, I see God's work. If someone seeks with an open heart they will find him.
Other versions of hell in other religions...well, hell is not a place to be regardless. That's what is great about a personal relationship with Jesus, take out what religion may fog your mind of and trust in the living word of God.
If you still do your research then check out Lee Strobel and his story.
All the best to u