George Sanders, the Magnificent Cad

Was this the movie that launched his career as "The Magnificent Cad" or was it "Rebecca" which came out two years earlier in which he had a more minor role? (His autobiography was titled "The Professional Cad".) I just saw this movie and he played a person who showed the epitome of "caddish" behavior just as his fellow artist in the movie played a person who showed the epitome of "selfless" behavior. Two extremes on display in one movie. I'm not sure which behavior is more unbelievable.