Charles Ellicott Commentary Exodus 21:8

"If she please not her master, who hath espoused her to himself, then shall he let her be redeemed: to sell her unto a foreign people he shall have no power, seeing he hath dealt deceitfully with her." — Exodus 21:8 (ASV)

Who hath betrothed her to himself. —The reading is to be preferred which gives the opposite sense—“who hath not betrothed her;” and the meaning is, “If the man, after purchasing the woman to be his wife, finds that he does not like her, and refuses to go through the ceremony of betrothal”—

Then shall he let her be redeemed. —Hebrew, then let him cause her to be redeemed: i.e., let him provide someone to take his place, and carry out his contract, only taking care that the substitute be a Hebrew, and not one of “a strange nation,” since her father did not intend to have her wed a foreigner.