“She is a veritable jewel.”
Agnes is the jewel in question and the metaphorical comparison here is being made by Horace. He makes this connection between his Agnes and a precious gem to Arnolphe while describing Arnolphe as a crazy man because at this point he remains unaware of that the crazy man he is describing is, in fact, Arnolphe.
"No flies on me."
This idiomatic metaphor appeared in Moliere’s 1662 comedy and then seemed to disappear for more than three centuries before experiencing a comeback in popularity through frequent use in the popular 1980’s TV show Moonlighting. A sight alteration was made in the interim; today, the phrase is more likely to be targeted some in a sarcastic manner toward another as “No flies on you.” Either way, the metaphorical intent is related to the concept of not being in a state of stasis which typically attracts flies. Arnolphe engages it early on as a companion to his more literal assertion “I’m marrying a fool” to indicate he is actively thinking clearly enough to avoid being made a fool of his wife by marrying a worldly woman.
Fops
Act Three commences with Arnolphe congratulating Agnes on following his instructions on how to handle the attentions of a man bent on seduction before launching into a lecture on the danger posed by fops. It is a chance to demonstrate once his talent for arranging words into poetic imagery and his description of these man buzzing Agnes is a masterpiece of metaphorical imagery that succinctly defines for any who may fail to understand exactly is meant by the term fop:
“I know fops: they’ve got
Ribbons and ruffs and plumes and God knows what –
Fine teeth; enormous wigs; great charm, of course –
But these are like the pads on a cat’s paws
And underneath those pads there are sharp claws.
They’re ravening fiends whose thirst is not for blood
But female chastity.”
Simple Girls and Clever Girls
The entirety of the slim plot on which the humor of this rhyme verse is the wisdom of choosing for a wife a woman who is smart enough to make a fool of a man or choosing a woman who is not smart enough. Therefore, much of the humor derived from metaphorical comparisons comes at the expense of comparisons of intelligence versus the lack thereof:
“A simple girl is easily put back
By two words on the straight and narrow track.
But clever ones are different kettles of fishes
Our fate will be attendant on their wishes”
What is a Marriage?
Arnolphe also turns his talents with words to metaphor to explain precisely to Agnes what a marriage is like. His figurative comparisons leave little doubt as to the potential life Agnes can expect with marriage to him:
“The private truckles to the officer;
Insignificant friars will defer
To reverend fathers; servants have to do
Exactly what their masters tell them to …”