A Falls Church woman who admitted killing her 18-year-old daughter last year--stabbing and beating her, then setting her on fire--made a tearful apology to a Fairfax County judge yesterday and was sentenced to 14 years in prison.

Gloria Prudencio, 43, pleaded guilty to second-degree murder and arson in the Dec. 22 death of her daughter, Yiti Arevalo, who was visiting from Honduras. Prudencio's attorney, Alene C. Grabauskas, said that his client suffered from periodic bouts of mental illness but that Honduran culture frowned on treatment or even the acknowledgment of a problem.

Todd F. Sanders, an assistant commonwealth's attorney, reminded Chief Circuit Judge F. Bruce Bach of the circumstances of Arevalo's death in her mother's third-floor apartment at Woodlake Towers on South Manchester Street. Although Arevalo had been badly beaten and stabbed, she was still alive when she was set aflame, Sanders said. "There's little that's more horrific than that," he said.

Prudencio's husband and other family members wept in court as she read a letter to the judge. "I felt that I had no right to continue living," she wrote, "because my baby certainly did not deserve to die. . . . There could be no one more remorseful than myself."

Prudencio said she did not remember the killing and offered no explanation or motive.