Thing is, when we accept Christ in our lives, and receive the Holy Spirit, our name is written in the Book of Life. If our current behavior effects our redemption, He would have to have angels sitting there erasing our names, then writing them back in and then erasing, then...Because at any point in your life, there are three possible states; you can be moving towards God, you can be moving away from God or you can be static in your walk.
If you want to believe it's as simple as "confessing with your mouth the Lord Jesus and believe in your heart that God has raised Him from the dead," then believe that.
I on the other hand will proceed with an abundance of caution to avoid paying lip service to God.
Redemption is a gift.
You left out the, "then you are saved" part when you quoted Romans 10:9-11. Christ said to believe that, because He said it, so, I believe it. And He put a period at the end of that sentence. Churches remove the period and hand us a list.
Christ makes it easy on purpose:
Matt. 11:28-30 “Come to me, all you who are weary and burdened, and I will give you rest. Take my yoke upon you and learn from me, for I am gentle and humble in heart, and you will find rest for your souls. For my yoke is easy and my burden is light.
And not meaning to offend, but isn't praying in rote giving God lip service?