For me, based on the way God (as represented in scripture) deals with mankind, there is no basis for confidence
Ain't that the truth! From cover to cover we see that God punishes sin, as we expect him to do; just as we expect our law enforcement to do as well. That's why confidence in yourself is totally misplaced; especially in light of the fact that God has offered a total pass to "whosoever".
Imagine the warmest fuzziest memory you have, perhaps from childhood. That's what God offers in his presence. I traded my shame for a crown of victory over sin. What did it cost me? Only this:
I can never take credit for the awesome blessings I enjoy.