That baptismal burial is symbolic of death. The death of who you were before. I'll compare this to the movie "The Matrix". When you are truly "born again", you will be outside of the "Matrix", and "awake".
The Matrix is the world, that the Bible says we should not be part of. Being worldly is not a simple as wearing baggy jeans or a short skirt. Being worldly is buying into the propaganda from the government run media, being "patriotic", celebrating pagan holidays, going to church on Sunday, pretending money is a "tithe", and otherwise being led to ignore Gods commandments.
There is no "sinner's prayer" in the bible. The washing away of sin happens when you actually divorce yourself from the Matrix of the World.
"Ye adulterers and adulteresses, know ye not that the friendship of the world is enmity with God? whosoever therefore will be a friend of the world is the enemy of God." ---James 4:4