Irony is a device authors use to create humor, suspense, or tension

Irony is a literary device authors use to create humor, suspense, or tension

Irony is a multi-faceted literary device that a writer uses to point out the discrepancy between reality and how things appear or what was expected

Explanation:

b. An extravagant, lustful, veteran widow.

The passage says that her features and clothes are bold and extravagant--she is wearing red stockings and has beautiful handkerchiefs, and her face has a lot of makeup on. 
It also says that she has had five official husbands and many partners, but the narrator is not going to tell the reader just how many.