Yes, one who does not have forgiveness of sins through Jesus Christ will pay for those sins eternally, because the sins are committed against an infinite God. Either way, the sins are paid. But we cannot say Clemenza, or librlH84, or Lexinom is eternally damned because we cannot lay claim on future events that may change hearts. We can only affirm that those with, by God's grace alone, a true and living faith in Christ that guides their lives and frees them from the concupiscence of the natural heart is a true child of God, and will never perish.
In the spirit of II Corinthians 5 I would add that many who take the label "Christian" conduct their lives practically as though they were atheists. To my shame I am guilty of this at times, and I would venture that most of us are. Seeing this probably only adds to the agnostic's confusion. But even this is under Divine control. All those He will save He will provide the right circumstances to bring them into His heavenly fold.
Wishing you all a good evening.
Then just WHY are all of us just wasting our time on this thread?