Personally, I’m anxiously awaiting the day I encounter somebody like that in real life. I’ll be tickled silly. Here’s why…
As usual, my first step is to establish what they believe about their god. (Omnipotent, Omniscient, All-Loving, etc.) Specifically, in this case, I want to make sure they believe their god knows exactly what they feel/think at any given time. Moreover, I want to establish if they believe their god judges them by their heart/thoughts/intentions. (See where I’m going here?.. wink-wink…) Once these parameters are dialed in and the target is locked, it’s time to drop the bomb. “Well, since you openly admit you are truly a vial and evil person at your core, then your god already knows this, and very likely it already has your spot reserved in hell. Have a nice day. 
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