Noel Coward created at least four comic plays that have staying power: "Private Lives", "Design For Living", "Hay Fever", and "Blythe Spirit". Three of them were turned into films, but the results are mixed. "Design For Living" was seriously bowdlerized by Hollywood, with a "bi-sexual" element eliminated. "Blythe Spirit" (which has a funny twist on how marriages always seem to sour as individuality is smashed) was done better, but it lacks a resolution that showed how the "so-called" tragedy of the plot actually benefits the hero, Charles Condimine. And "Private Lives", while having a degree of elegance from it's stars, is not brittle enough.
Coward was a master of developing attitude through his dialog. He seems to have modeled his handling of his characters on William S. Gilbert (of Gilbert & Sullivan fame). Gilbert had always insisted when directing his own plays that the characters retained the seriousness of their own characters and points of view. This worked in the Savoy Operas quite well, and Coward (who wrote musicals as well as comedies) picked up on it. When Elyot and Amanda flow from their sexual cosiness into their inane arguments, both of them are firmly sure that they are in the right. But being in the right is not enough: they have to be above it all by their social snobbery in the same dialog. If you don't insist on this in producing "Private Lives" the play may remain amusing but it's snap is lost.
Example:
Amanda: "I heard you went to Asia"
Elyot: "Yes"
Amanda: "How was China?"
Elyot: "Very large."
Amanda: "How was Japan?"
Elyot: "Very small."
Brittle and short and to the point - and it does give an impression of what Elyot noticed (very little really) of two major Asiatic cultures. It is also quite dismissive - the teaming millions of Asia are reduced to four meaningless words. This dialog appears in the film version of PRIVATE LIVES, but the sharpness required for "Very large" and "Very small" is not quite there. So the effect of the dialog is diminished.
Robert Montgomery usually played in MGM films at this time as weaklings (like in "The Big House") or as upper crust cads (like in "The Divorcée"). He demonstrated an agreeably sophisticated cynicism in his films, and was slowly building up an acting ability that would turn into strong dramatic performances in "Night Must Fall" and films like "They Were Espendable" later on.
Montgomery came from a wealthy family, so his polished elegance was real. But he was an American, and Elyot's brittle snobbery is more likely to be found in English acting. The role of Elyot was played by Noel Coward originally. MGM either never thought of asking him to play the role, or could not get him for some reason.
Norma Shearer was a better than average actress, and she had played upper class Americans (like her betrayed wife in "The Women"), but she too is not English (she was Canadian). She too can't quite match the flash of snobbishness in Amanda's role that was brought to it by the original player, Gertrude Lawrence. As Lawrence and Coward were close friends in real life, they brought even more to the roles than Montgomery and Shearer could have brought.
The result is that the film is very amusing - otherwise I would not give it an "8". But it could not reach the divine heights that Coward and Lawrence brought to it.
As for the supporting couple, Reginald Denny and Una Merkle, they are adequate for their hapless roles as the newlywed partners of Elyot and Amanda. But Una Merkle as Sybil is too middle American a personality, and only is able to hint at Sybil's "fade - in - the - shade" fate when compared to spitfire Amanda. Denny was a workmanlike Victor, and (as the only English person in the cast's leads) a touch of reality to the film. But Victor's smoldering anger is barely touched on in his performance (he's too much of a gentleman). Oddly enough, MGM never thought of using the actor who originated Victor's character on stage - another friend of Noel. His name was Laurence Olivier.
