It is praiseworthy to believe that Jesus is the Son of God; however, this acknowledgement does not save the soul. Even the demons believe, and tremble.
Spiritual rebirth starts with the belief that Jesus is the Son of God. What saves is a personal relationship with Jesus Christ. That relationship comes about by repentance from sin and by asking Christ to become Lord of your life.
“I have been crucified with Christ; nevertheless, I live. Yet not I, but Christ lives in me. And the life I now live in the flesh, I live by the faith of the Son of God” (Gal. 2:20).
“For if, when we were enemies, we were reconciled to God by the death of his Son, much more, being reconciled, we shall be saved by his life” (Rom. 5:10).