Jesus made several promises to St. Faustina and anyone who prayed the Divine Mercy Chaplet with a sincere faith.
Just one verse each day.
St. Faustina Kowalska, a Polish nun during the 1930s, received several private revelations from Jesus. She wrote down these visions in her Diary, which later became the foundation of the Divine Mercy Chaplet, as well as Divine Mercy Sunday.
She recorded in her Diary several promises that Jesus made to her and anyone who prayed the Divine Mercy Chaplet with a sincere and honest faith.
As with similar private revelations, Jesus did not institute a short-cut to Heaven, where a dishonest person can mechanically say the words of the Chaplet and somehow gain Heaven by their own efforts.
These promises are always gifts given to an individual who is ready to receive them.
Here are the three primary promises Jesus gave to St. Faustina.