“Everybody has a right to make a mistake,” Gulpari Farziyeva, 31, said of her journey to Syria, and marriages over six years to a succession of Islamic State militants. Even three weeks into treatment, she seemed remarkably untroubled by the militant group’s ways.

One day in Syria, she recalled, she was host at a dinner party at her apartment. While cooking dumplings and baking a cake, she dashed out to the market for a tablecloth she had forgotten to buy on an earlier trip.

At the market she saw a ghoulish scene, “five or six headless bodies,” on the ground along with “a lot of blood.” A public execution had taken place between her two trips. She averted her eyes, she said.

Nonetheless, she said, she bought the tablecloth and said the dinner party went swimmingly, with all the guests having a good time.

At another point, Ms. Farziyeva said, a militant living across the street was presented with an enslaved Yazidi concubine as a gift. “I was sorry for her,” she said. “She was a woman, too.” But as a non-Muslim, she said, the woman could not be taken in as a wife, with such rights as that entailed.

In the end though, Ms. Farziyeva expressed repentance. “I haven’t met any sister with some ideology left inside her,” she said. “We understand we were wrong.”