I'm surprised that no one has picked up on the fact that Nora Prentiss is merely an updated version of Theodore Dreiser's classic Sister Carrie. Since Dreiser had died a couple of years before, he didn't pick up on it or Warner Brothers would have had a libel suit on its hands.
Sister Carrie was set in the turn of the last century and dealt with Victorian mores. Even in post World War II America, it seems that not much has changed. Respectable and proper Kent Smith is a forty something doctor, married with two children, in a respectable middle class rut. He's about to break loose for some big life crisis. The catalyst for that is Ann Sheridan in the title role. Sheridan is a sultry night club singer who gets hit by a cab and is treated in Kent Smith's nearby office.
Had the film been made at Columbia, Rita Hayworth would have been ideal for the lead. But Ann Sheridan does do a good job and even does her own singing. Hayworth would have made the film a classic.
The film does descend into melodrama though moving far afield from the social commentary that Theodore Dreiser had in mind. But Kent Smith's character's degradation is as complete as Dreiser's George Hurstwood.
I would recommend seeing this film and the film that Sir Laurence Olivier and Jennifer Jones did, Carrie, and comparing the two versions.