Jael, who killed Sisera, was the wife of whom?

Answer: Heber the Kenite

Sisera fled to Jael's tent because there was peace between Jabin king of Hazor and the house of Heber the Kenite.

“Meanwhile, Sisera had fled on foot to the tent of Jael, the wife of Heber the Kenite, because there was peace between Jabin king of Hazor and the house of Heber the Kenite.”— Judges 4:17 (BSB)