As many saints like padre pio and the children of fatima stated, the rosary saves souls. So I know it's important to say the 15 decade rosary for the salvation of others.

Sorry, if this sounds selfish, but are the 15 promises of the rosary genuine, or just internet garbage. As someone who has sinned terrible in my life, I'm hoping the rosary is my lifeline  

From someone who contribute my conversion, and the everything in turning my wicked life around to Our Lady’s Holy Rosary, I couldn’t recommend 15 decades a day more. You have every reason to believe the 15 promises, only modernists would cast them aside. This is the devotion that is so badly needed and that Our Lady asked for many times over. Sister Lucy had this to say in her last public interview:

“Prayer and sacrifice are the two means to save the world. As for the Holy Rosary, Father, in these last times in which we are living, the Blessed Virgin has given a new efficacy to the praying of the Holy Rosary. This in such a way that there is no problem that cannot be resolved by praying the Rosary, no matter how difficult it is - be it temporal or above all spiritual - in the spiritual life of each of us or the lives of our families, be they our families in the world or Religious Communities, or even in the lives of peoples and nations.”