The Bible is clear that no sinner can be saved apart from explicit faith in Christ (Romans 10:14). Jesus himself said, “He who believes in Him is not judged; he who does not believe has been judged already, because he has not believed in the name of the only begotten Son of God” (John 3:18). But it ought to kept in mind that according to Hebrews 11:6, he rewards those who earnestly seek him. Thus it follows that if any do earnestly seek, they will be accorded the opportunity to place faith in Christ.
The false assumption, from which this question gains its rhetorical force, is that people go to Hell because they fail to believe in Jesus. Strictly speaking, this is false. Since one's sins require judgment (as demonstrated elsewhere on the site), it is one's sins as such that serve to merit punishment and thus result in one's condemnation (rather than any sin particular).
As also demonstrated throughout the site, it is simply not possible for God to save sinners apart from their acceptance of Christ's atoning work. However, as also shown elsewhere, God ensures that the truth of the gospel is revealed to those who cease to stand in opposition to him.