Because we are declared just by the court of heaven, having the record of our debt to God being canceled, and the righteous life and deeds of Jesus being credited to our account.
Once we are declared righteous by God, we are saved.
If someone who claims to have put their trust in Christ for salvation or who even merely claims to believe in God is going to hell, they are not saved.
No saved person goes to hell. Hell is what we're being saved from.
You can't be saved (from hell) and end up going there.
If they think that someone who is saved is going to hell, I'd sure love to know what the heck the saved person is then saved from.
How many years has my tagline told you this???
And if God promised to forgive sins and never bring them up again I would like to know how they think He will bring them up at some judgement.