Like By The Morning Star
This comedy of manners read like the author was channeling Eva Ibbotson, and Shakespeare frequently popped by to give plotting advice. The style is slightly more modern in tone than Ibbotson -- not because this is set before World War II, rather than World War I, but because the mild-mannered hero doesn't indulge in old skool jealous rages, as virtually all Ibbotson heroes do. Other than that, the characters bear a striking similarity to those of A Countess Below Stairs (reprinted as The Secret Countess) and Magic Flutes.
It's often funny and charming, in a deliberately mannered and utterly ridiculous way, but the mistaken identities and tangled plots lead me to an expectation of romantic angst that wasn't fulfilled. Consequently the ending fell flat and the romance seemed ultimately disappointing. I also thought the author came across as a little self-conscious about the many silly misunderstandings, by explaining them too much. But it's definitely worth a read if you enjoy this sort of thing.