Catherine Kieu Becker, 48, made her initial court appearance in the afternoon, but she did not enter a plea. She appeared briefly in Orange County Superior Court in a navy blue jail jumpsuit, hiding her face with her long, dark hair.
"It's hard to believe what would motivate a person to do this sort of thing," the district attorney's chief of staff, Susan Kang Schroeder, said outside court. "It's one of the worst things you could do to a person short of killing him."
She was appointed a public attorney to defend her and was denied bail. Arraignment was rescheduled for July 22.
Becker was charged with one felony count of torture, one felony count of aggravated mayhem and sentencing enhancements for great bodily injury and personal use of a knife. She is scheduled to undergo psychological evaluation.
The victim is said to be in good condition.
The Associated Press contributed to this story.