Christian Question...?

God says that some of us will not be saved. All of us will endure some suffering in our lives. I am not an opposer of Christianity, I go to church but I still have questions.... One of them being, God is our creator, we are his children...Why does he allow for some of us to not be saved, to endure the pain of the underworld for eternity? He created us, knowing our hearts from the beginning. He knew everything from the beginning, yet creates some of us, knowing that our destiny is to go to eternal suffering. Why is this?