Let’s read it, shall we?
“That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved.”
It is SOO easy!
Confessing with your mouth means “I believe that Jesus is real and that He is God!” You can’t become Born Again if you don’t believe that Jesus is real!
The second part, “and shalt believe in thine heart that God hath raised him from the dead”, means just what it says- believe that God rose Him (Jesus) from the dead and believe that He is real, and then, and only then, will you be saved.