Imagine a scenario in which there is a man we will call him Sam. Sam is a good boy and grows up to be a firefighter who saves many lives and often anonymously donates to different charity funds. He also denies god in every form way or fashion he despises god for some reason. He has done good things with his life and saved many people but he will burn eternally in agony. I know that you said it is impossible to be a perfect being but shouldn't you try!!!!
You will find that there is disagreement even among conservative Christians about how exactly salvation works. This is because different Churches teach slightly different things. Sometimes even the slight differences end up producing important differences in how we view the crucial issues.
The bible begins with the story of Adam and Eve. You have probably at least heard of this story. The story tells how mankind fell from grace. Adam and Eve rejected God because they chose to decide for themselves what was right and wrong. They chose to live apart from God.
This is at the root of all human evil. God is the only source of goodness and when mankind chose to seperate from God, it also seperated us from the ultimate source of goodness.
The only way to ever regain that, is to come back into relationship with God. On his own, without God's help, man is incapable of doing this. Further, man was condemned because of his evil, and deserved judgement.
God, on the other hand wanted to save mankind and so he formulated a plan to restore humanity to relationship with him. The plan was that God would become a man himself, and he, though he was perfect, would die to pay the penalty of our sins.
Man kind was already cut off from God, which is a kind of death, so when Jesus Christ, God in the flesh, died, he not only paid the price of our evil, he also rescued us from our death. Because he was God, death could not hold him, his life was indestructible, so by dying, he defeated death and he is able to rescue all those who come to him from death.
The way that we are saved is by coming into relationship with Jesus Christ. But its not simply saying a few words, the kind of relationship that we are called to is much more profound than that. Through it we are united to Jesus Christ. In a sense we become a part of Him, and as a result we share in his life, and his goodness.
If we do this, then we will also be transformed by his life and his goodness. But this relationship requires submission on our part to the Lordship and Kingship of Jesus Christ.
Those who do not, will never be transformed, and they will never come back into relationship with God.
The reason that these people will not come into this relationship is that they prefer to burn independantly rather than live in submission to God.
I firmly believe that those who end up in hell would not serve God willingly, even after they had experienced hell if they were again given the choice.
Also, you raise the issue of a person who seems good, and how can they be condemned? The answer here is that we human beings are made in the image and likeness of God.. even in our fallen state, even in our evil, there is still a faint glimmer of God's image, that gives us the capability for nobility, and 'good deeds'.
This remains because God, while the world lasts, restrains evil and inspires people through what is called common grace. In other words, even a person who totally rejects God, while they live still experiences God's grace and their character is still affected by God's grace.
However, were that grace removed, as it will be after their final rejection, their true evil would shine through.
