I Was an Undercover Slave (1994)

Policewoman Sabrina attempts to infiltrate a white slavery operation by allowing herself to get restrained and beaten for days on end. Darlene, the mistress, informs her she is being domesticated in preparation for "buyers" who appreciate "pretty young girls" like her... to which Sabrina replies, "That's barbaric!" A former slave is brought in for further education, and finally the two (joined by the mistress's assistant, Yvette) are put on the buyer's block.