Where does “सदैव” come from?

सदैव (Sanskrit) comes from Sanskrit एव, from Sanskrit इ, from Proto-Indo-European h₁éy- — he, this.

सदैव (Sanskrit): always

Definitions

Step	Language	Word	Meaning
1	Sanskrit	एव	so, just so; indeed, truly; just, exactly, as;...
2	Sanskrit	इ	to go
3	Proto-Indo-European	h₁éy-	he, this

सदैव — Etymology, Origin & Word History | Etymology Explorer