Sleep, My Love (1948)
OK, it's a no brainer. I love Claudette Colbert, I love this post-war period, and I love Douglas Sirk, the director. So it only figures that this unfolds in a delicious way.
The closest film to this is "Gaslight," which George Cukor makes into something more intense and memorable than this. But "Gaslight" is burdened by a kind of contorted plot--the reasoning behind the fake madness is some crazy lost jewel. This one, by fortunate contrast, is a really believable plot, and Colbert is faced with a very normal plot of a husband out to drive her away.
There are some weaknesses--the husband's girlfriend is pretty stiff, the Chinese pal is decent but sort of tacked on, and the overall development of things is too linear for a second viewing. But as a straight up drama, from start to finish, it's really strong. And a surprise for me was how charming in a low key way was Robert Cummings, the white knight of the story. Colbert's husband was played by the more famous Don Ameche, who is fine, though you get a sense he's going through the paces of a part, something he wasn't quite invested in.
The director is famous for his later dreamy, drippy soap opera movies that are quite something on their own terms, but this is good, and an important one to see if you like his work. For me, above all, is just another great Colbert appearance. First rate in many ways.