Sharon Whit (Ilene Graff) is the main villainess from "Bad Marsha," episode 6.18 of Mr. Belvedere. She is an imprisoned criminal who has been convicted of armed robbery, grand theft, and felonious assault, and she was Marsha Owens' first criminal client.
Marsha had never met Sharon, so when they first met, Marsha was very surprised to see that Sharon looked just like her. During their sit down interview, Sharon gave a sob story about what she had been missing during her imprisonment--after which she grabbed Marsha's attache case and knocked her out. The villainess switched clothes with Marsha and made her escape, leaving Marsha in prison. Once she reached the Owens home, the evil Sharon planned to gain the family's trust and pose as Marsha, while eventually robbing them blind.
The strange behavior of "Marsha" was noticed by the family, especially Kevin (who Sharon hit on) and Wesley (who received praise from Sharon over his stint in detention). The most suspicious was Mr. Belvedere, and after he walked in on Sharon making a phone call to her partner, he talks Sharon into cooking a lavish dinner--after Sharon asked for his advice for convincing George to allow her to buy a big screen TV. The family was impressed by Sharon's cooking, and as Mr. Belvedere pointed out, that was what gave Sharon away--as Marsha is a terrible cook. After overhearing the group discussing exposing Sharon, the villainess made her escape, leaving Marsha (who finally freed herself from prison) to receive the family's wrath, as they believed she was Sharon.
The episode ended with the events being part of Marsha's nightmare, as she was nervous about her first criminal case. However, when Marsha was given an attache case as a gift, she noticed a dent in it, as it was the same one Sharon used to knock her out.