I think this question is probably asking what happens to people who don't hear about Jesus at all? Does God expect people to believe something they've never even heard of?
The Bible says...
Romans 10:13-14
'Everyone who calls on the name of the Lord will be saved.'
How, then, can they call on the one they have not believed in? And how can they believe in the one of whom they have not heard? And how can they hear without someone preaching to them?
People need to hear about Jesus in order to ask him to save them from their sin. This is why Christians from the beginning have worked hard to share the great good news about Jesus with everyone they can. That's why the Bible goes on to say...
Romans 10:15
And how can anyone preach unless they are sent? As it is written: ‘How beautiful are the feet of those who bring good news!’
If Jesus really is God and really can make us friends again with God, then telling others about him is a privilege and a joy for every Christian.
Christians want to make sure everyone has had the chance to hear, understand and respond to the good news (or gospel) of Jesus so that they too can have forgiveness and friendship with God. That's why Christians and churches are busy all over the world telling people about Jesus.
But there are still places today where this hasn't yet happened. They're sometimes called "Unreached People Groups". According to a Christian organisation called Global Frontier Missions...
"It is estimated that of the 7.75 billion people alive in the world today, 3.23 billion of them live in unreached people groups with little or no access to the Gospel of Jesus Christ."
Brilliant! I'm so glad there are so many Jesus-followers, churches and organisations who are on a mission every day trying to share their faith in Jesus with everyone who needs to know him.
Romans 10:15
... As it is written: ‘How beautiful are the feet of those who bring good news!’