Where does “sonts” come from?

sonts (Proto-Italic) comes from Proto-Indo-European h₁sónts, from Proto-Indo-European h₁ēs-.

Ancestry of “sonts”, step by step

Step	Language	Word	Meaning
1	Proto-Indo-European	h₁sónts	active participle of *h₁ésti; being, existence;...
2	Proto-Indo-European	h₁ēs-	—

sonts — Etymology, Origin & Word History | Etymology Explorer