Mary Astor was a lady.
Even in parts where she played the other woman, there was an inherent goodness to her. You can see for instance in "Dodsworth" how Walter Huston can reject bored, flighty Ruth Chatterton for grounded, dewy Mary. Along this time in her career she somehow managed to survive a career-killing scandal involving her husband suing for divorce; attempting to enter into evidence her notes on her affair with George S. Kaufman, humiliatingly listing his prowess. The Judge ordered her diaries sealed.
She spent the forties memorably playing against Humphrey Bogart and others as the alternately poisonous and perfect female, and after admitting alcoholism in the 50's she capped her career as the destitute "all I have is ruined finery" Maguffin in "Hush... Hush Sweet Charlotte".