i'll tell you the hell - a cocky way to say you're going to explain why something is

a cocky way to say you're going to explain why something is so stupid that it makes no sense at all

I'll tell you the hell, it's because you're dumb enough to believe that.

I'll tell you the hell, it's because you didn't listen when I said it was dumb.

I'll tell you the hell, it's because you're still here, and that's a crime.