Converting sinners through the Rosary?

[PetrusRomanus]

Which Saint says something to the effect that the Rosary, or 15 decades of the Rosary every day, will convert even the most hardened sinner?

I’m also aware that there are novenas that also state this. Which are they?

If you commit yourself to praying the Rosary/novenas to convert a most hardened sinner, is that good for only one person or can it be for multiple people?

 

[abon12]

I offer up my rosary everyday for a lot of things, like the salvation of all souls and the restoration of the culture of life.
Don’t worry whether or not God can handle your petitions. Because he can. He’s God.
Offer Him everything and let him worry about that.
Btw, this was former advice a priest gave me, when I asked him if I should offer up me going for a jog. His response was let him handle that, lol.

I bet it was Mary who said that. Maybe to one of the people she appeared thru apparitions. Maybe Our Lady of Fatima?

 

[ready]

Which Saint says something to the effect that the Rosary, or 15 decades of the Rosary every day, will convert even the most hardened sinner?

I’m also aware that there are novenas that also state this. Which are they?

If you commit yourself to praying the Rosary/novenas to convert a most hardened sinner, is that good for only one person or can it be for multiple people?

It is my understanding that you can make your intentions for multiple people.