You may also be looking for the TV character Ettie Weston. Bernadette Weston, also known as Ettie Weston, is the secondary female lead in the first two Murdoch Mysteries films, while the primary lead in the third. She is characterized by a sharp tongue and a kind heart.
Background
Ettie has been on the streets since she was 14, after she had an affair with a (black) sailor. She was a prostitute for much of that time, sharing sordid rooms with her friend Alice Duff. She first came to Murdoch's attention when a murdered girl, Terese LaPorte, was found dead--and naked--right behind the brothel in which Ettie and Alice lived. After a bit of digging, Murdoch discovers that Alice and Ettie stole Terese's clothes and hid them, for the time being, in the outhouse. During the course of the investigation, Alice is murdered, and Ettie is very nearly killed as well, by the villainous manservant Canning. Murdoch manages to save Ettie's life at the last minute. Ettie was next found working at Lady Jane's Music Academy, a high-class brothel. She helped Murdoch to find Oliver Winnett's killer. Finally, Murdoch came upon her as "The Incredible Madame Bernadette", a fake medium who describes her job as "giving hope" to those in need.
Personality
Ettie's naturally contentious relationship with law enforcement has made her aggressive to the point of being shrewish, but this is all a façade. She is a genuinely caring woman who is in love with Murdoch, and hates the fact that she is too low-born for him to love her in return. In truth, Murdoch does love her, but can't begin a relationship with her while she is still a prostitute. Once she becomes a respectable fake psychic medium, their relationship seems to have some hope, especially after the departure of Dr. Julia Ogden, with whom Murdoch has a stuttering almost-relationship in both "Except the Dying" and "Poor Tom is Cold." Ettie also has a wicked sense of humor, for instance referring to the cad footman Meredith as "Merry-Dick" (which Murdoch also calls him). Murdoch is also encouraged in his relationship with her when he discovers that Julia has described him as "stuffy".
Ettie also has a son, Freddie, who, like his father, is black. This meant that after he was born, no families would adopt him and Ettie had to pay $8.00 a month for the last seven years for his upbringing. Mrs. Shaw, the woman who "adopted" Freddie, told Ettie that he was dead for obscure reasons (most likely because she didn't want Ettie to know that she treated Freddie as a servant and didn't use the money to help with his upbringing), and Ettie became incensed, and shoved Mrs. Shaw, causing her to bang her head upon the fireplace. Later in the investigation, Murdoch figured out that Freddie was Ettie's son, and was able to reunite the pair.
Relationship with Murdoch
From the start, Ettie has a love-hate relationship with Murdoch, alternating between making advances on him and screaming at him. She dislikes the fact that he seems to look down on her for being a prostitute, even though she eventually realizes that he is simply worried about his position as a policeman.
The film "Under the Dragon's Tail" ends with Murdoch, having been knocked senseless in a boxing match, resting his head in Ettie's lap. Since Dr. Ogden has returned to Europe for an extended six month stay, and since "Under the Dragon's Tail" is the last film in the series, we can only speculate as to what happened with their relationship.
Similarities to Characters in the TV series
Ettie's role as a (phony) psychic appears to have been adapted into the recurring character of Miss Pensell. Her sense of humor also seems to have been given to Dr. Ogden, played by Helene Joy, as hers is a more impish character than Keeley Hawe's interpretation of the role. Although a character called Ettie Weston does appear on Murdoch Mysteries, she only appears in one episode, "The Green Muse", and is played as a supporting character by Krista Bridges. Neither Dr. Ogden nor Constable Crabtree know of Ettie, which directly contradicts the events of all three films.