This is a very common question. I get it quite often at the site. It is a good question.
My response is that I leave such decisions in the hand of God. I am not the judge. I am glad that I am not the judge. I assume that God knows what he is doing. God is just. He can take care of the situation of a person who never heard of Jesus. Such a person, I assume , will be judged according to what he knows and "according to his conscience." (Romans 2:5-16). The one thing I know for sure is that the best and the only hope for people is salvation through Jesus Christ (Acts 4:12, John 14:6). The best hope for such a person is for one of us to go out there and bring the news of Jesus to him or her. It is my job to do all I can do to reach out to the lost and to try to help people to be saved. It is not helpful for me to be paralyzed by concerns over things I have absolutely no control over, such as people who I have never met and never will meet. Please, let us leave such situations over which we have no affect in the hands of God.
By the way, FYI, this question is becoming decreasingly relevant. Given modern communication, the number of people in the world today who have not heard of Jesus and who know literally nothing about Christianity is very close to zero.
One might say it is unfair, that God might judge the world before some people (who are so very remote) ever get a chance to hear the message. What do you think?