An Introduction to the Devout Life continues, with a little prayer to say as an act of contrition during Confession.
In St. Francis de Sales’ time, people often were comforted by prayers that sounded like legal binding contracts, because it stopped them having to worry about contingencies. Since he’d been a lawyer, he could pour on the legalese for worrywarts as much as they liked. (But if you don’t find this sort of language helpful, just say any other Act of Contrition prayer or make one up.)
Book 1, Chapter 20: A protestation for fixing in the mind a resolution to serve God after Confession.