Victor Hugo said, "The supreme happiness of life is the conviction that we are loved; loved for ourselves, or rather, loved in spite of ourselves."
I mention this because it seems to me that only the Christian faith gives us precisely such assurance of being loved. Only Jesus Christ, in dying for us who were rebellious, unlovely, and sinful, demonstrated the supreme love that can give us the supreme happiness.
God, who knows our every thought, who knows us just as we are, not as we would like to be or wish we were--died to win us for heaven, and for Himself.
"Oh, what manner of love the Father has bestowed upon us!"