"Why is it reasonable to believe in prisons, but not in the hell?"

[rado84]

Prisons exist, you can see them and touch them. Humans manage these prisons. People have returned from prisons and sometimes they tell their story what it's like in prison. People have spent part of their lives in these prisons and walk freely now (like Varg Vikernes who I respect mostly bc he likes to burn churches).
Nobody has yet returned from heaven or hell to say what it's like in there, not to mention you can't see either or touch either of them, therefore they don't exist.