Where does “sentjō” come from?

sentjō (Proto-Italic) comes from Proto-Indo-European sent-, from Proto-Indo-European h₁es- — to be.

Ancestry of “sentjō”, step by step

Step	Language	Word	Meaning
1	Proto-Indo-European	sent-	to head for, to go, to travel; to feel
2	Proto-Indo-European	h₁es-	to be

sentjō — Etymology, Origin & Word History | Etymology Explorer