Where does “հաւաստիք” come from?

հաւաստիք (Old Armenian) comes from Old Armenian հաւաստի, from Old Armenian հաւաստ, from Old Iranian ham-vasta-.

Ancestry of “հաւաստիք”, step by step

Step	Language	Word	Meaning
1	Old Armenian	հաւաստի	certain, true, indubitable, sure, convincing,...
2	Old Armenian	հաւաստ	certain, true, indubitable
3	Old Iranian	ham-vasta-	—

հաւաստիք — Etymology, Origin & Word History | Etymology Explorer