If someone can freely choose God, he must also have the possibility to reject him, otherwise the choice is not free. Someone who consciously and definitively rejects God and his love, chooses hell. Actually, we do not know exactly what hell looks like.
We know it is a place without joy, because true happiness can only be found with God. Hell is full of pain and suffering. Worse, people there are forever lonely, because selfishness prevails. A greater contrast with heaven is inconceivable! Fortunately, while we are here on earth we still have the option of showing remorse for our sins and receiving God’s love and forgiveness.