Casilda. But which is it? There are two of them!
Duke. It is true that at present His Majesty is a double gentleman; but as soon as the circumstances of his marriage are ascertained, he will, ipso facto, boil down to a single gentleman — thus presenting a unique example of an individual who becomes a single man and a married man by the same operation.
Duchess. (severely) I have known instances in which the characteristics of both conditions existed concurrently in the same individual.
You can find plenty of performances on Youtube, but I'd suggest keeping a copy of the libretto handy to carry you through some archaic phrases here and there.