Where does “sahetu” come from?

sahetu (Pali) comes from Pali hetu, from Sanskrit हेतु, from Sanskrit तु, from Sanskrit त्वम्, from Proto-Iranian tuHám, from Proto-Indo-Iranian túH, from Proto-Indo-European túh₂ — you, thou.

Ancestry of “sahetu”, step by step

Step	Language	Word	Meaning
1	Pali	hetu	cause, reason; condition; motive
2	Sanskrit	हेतु	"impulse", motive, cause, cause of, reason for;...
3	Sanskrit	तु	pray, I beg, do; but; and
4	Sanskrit	त्वम्	you, thou
5	Proto-Iranian	tuHám	—
6	Proto-Indo-Iranian	túH	you, thou
7	Proto-Indo-European	túh₂	you, thou

Words derived from “sahetu”

ສາເຫດ
សាហេតុ

Every word from Proto-Indo-European túh₂ →Every word from Proto-Indo-Iranian túH →Every word from Proto-Iranian tuHám →