'Pledged' in the Bible

Lot went out, and spoke to his sons-in-law, who were pledged to marry his daughters, and said, "Get up! Get out of this place, for Yahweh will destroy the city." But he seemed to his sons-in-law to be joking.

Also, your servant pledged his own life as a guarantee of the young man's safety. I told my father, "If I don't bring him back to you, you can blame me forever.'