Hi Mike,

The 15 promises were revealed by Our Blessed Mother to St. Dominic in a private revelation during the Albigensian heresy. A few hundred years later she also revealed them to
Blessed Alan de la Roche, also known as Blessed Alan De Rupe.

This is a faithful site that has information on your question.

Being a private revelation, no Catholic is bound to believe the promises at all. though I personally encourage everyone, Christian and non-Christian alike to pray the Rosary on a regular basis.

Our Blessed Mother told Dominic that:

"I want you to know that, in this kind of warfare, the principal weapon has
always been the Angelic Psalter [the Rosary], which is the foundation-stone
of the New Testament. Therefore, if you want to reach these hardened souls
and win them over to God, preach my Psalter."

For more on its history read this MS Word document.

I hope this answers your question.

Mike