A Lonesome Lady (2008)

Original title: おひとりさま -三十路OLの性-

A career woman who is a project leader at an urban development company. She gives orders to her subordinates efficiently and speaks frankly to the president. In fact, she used to have an affair with the president, but her high sense of elitism became an obstacle and the relationship has now ended. However, because of her high sense of elitism, no man talks to her in a friendly manner anymore, and she is a lonely "solo person" in her daily life. One day, while drinking alone at a bar, she meets a cool-looking man, but he is a member of the Yakuza. The man has been entrusted by the gang with managing the women who are prostituting themselves as streetwalkers in the area. Drunk, she walks through the streetwalker area. The man says to her, "Lonely elite lady, why don't you try selling yourself?" and she says, "I'll do it." From there, she begins her double life, day and night. However, one day, one of the women standing in the area is brutally murdered, and the problem begins to spread...