Your Désilets is certainly from the province of Quebec as the surname "Désilets" was created there and not in France. The ancestor was likely Antoine Desrosiers.
I have a Désilets family in my data that left Nicolet after 1865 and that left no more traces that I could find in Quebec after 1865. That happened often with families moving to US. And this family has a Virginie born in 1847 :
Guillaume Désilets b 19-09-1819 bap 20 Nicolet (Nicolet) d 1875 (Pierre Désilets & Josephe Lafond) m 20-10-1840 Nicolet (Nicolet) Émérance Lecomte (Antoine Lecomte & Théotiste Lord
Children: Émérencienne, 1841 M Clotilde,1843 Guillaume Jean,1846 M Virginie, 1847 M Vénérande,, 1850 Zoël, 1851 Florence, 1853 Zoé,, 1855 Joseph Philippe, 1855 M Louise,1856 M Elzire, 1857 Victorine, 1860 M Eugénie,1862 Joseph, 1865
You may be able to identify some of these children when marrying in the area of Manchester as some of them must have done.
Another way would be to check the (Catholic) church baptism records of Virginie's children. The records normally show the names of the godparents (sponsors) of the child. Those are often grandparents or uncles or aunts of the child and if you're lucky, the relationship to the child may be stated. If you should find brothers or sisters of Virginie among those godparents that would be proof that I provided you with the right family. If not, any other Désilets named as godparents would be clues to help look for another family.
If this is the right family, I can provide you with 6 more generations.