In Chapter 1, Thackeray introduces the reader to the two main characters of his novel: Becky Sharp and Amelia Sedley. When introducing Amelia, he uses a combination of hyperbole and satire to describe her and establish her as a foil to Becky:
But as we are to see a great deal of Amelia, there is no harm in saying at the outset of our acquaintance, that she was one of the best and dearest creatures that ever lived; and a great mercy it is, both in life and in novels, which (and the latter especially) abound in villains of the most sombre sort, that we are to have for a constant companion, so guileless and good-natured a person.
These first few lines of description are an exercise in overstatement, as Thackeray carefully sets his reader up for Becky and Amelia's dueling narratives. From the start, Amelia seems to be a paragon of virtue—by describing her as utterly "guileless" and "one of the dearest creatures that ever lived," Thackeray uses hyperbole to distinguish Amelia from the other residents of the Vanity Fair. He even primes the reader for the drama to come, pointedly contrasting Amelia with the countless "villains of the most sombre sort" that abound in novels just like this one. Though he doesn't say it outright, Thackeray is plainly alluding to Becky in this remark. As the reader will soon discover, Amelia is a foil to Becky—and vice versa: where Amelia is good-natured and kind, Becky is a deceitful "young misanthropist," not the least bit "kind or placable." Where Amelia's life collapses at the financial ruin of her father, Becky manipulates her way into the upper stratospheres of London society.
Later in the same sequence of exposition, Thackeray offers the reader a satirical vision of his protagonist, in the negative, when he describes everything that Amelia is not:
As she is not a heroine, there is no need to describe her person; indeed I am afraid that her nose was rather short than otherwise, and her cheeks a great deal too round and red for a heroine; but her face blushed with rosy health, and her lips with the freshest of smiles, and she had a good pair of eyes, which sparkled with the brightest and honestest good-humour, except indeed when they filled with tears, and that was a great deal too often;
The pointed observation that Amelia is "not a heroine," even as Thackeray constructs Amelia to be an embodiment of all that is good in the world, betrays his narrator's distaste for literary convention and Thackeray's vision for a novel with no hero. Thackeray's reliance on Amelia's humble physical description, in order to distinguish Amelia from "heroine"-types, is a careful work of satire—even as he assures the reader that Amelia will be a major subject of the novel, he insists that she does not look the part. In this playful way, Thackeray prepares his reader for a novel that eschews tired archetypes and instead presents a set of deeply flawed and human characters in all their complexity and contradiction.
In Chapter 18, Amelia's world threatens to collapse around her when her family is ruined at the outbreak of the Napoleonic wars. Amelia's husband, George, driven by his own greed, refuses to empathize with her predicament—a twist that Thackeray takes as an opportunity to satirize the uneven power dynamics of 19th-century marriage through verbal irony and hyperbole:
To whom could the poor little martyr tell these daily struggles and tortures? Her hero himself only half understood her. She did not dare to own that the man she loved was her inferior; or to feel that she had given her heart away too soon. Given once, the pure bashful maiden was too modest, too tender, too trustful, too weak, too much woman to recall it.
The narrator sees Amelia as a paragon of virtue and tends to convey this in hyperbole, as above—Amelia seems to be too perfect ("too modest [...] too much woman") to fall out of love with George, and despite his awful treatment of her, Amelia maintains that he is her hero. Amelia may be earnest in her convictions, but the narrator drenches his own observation of Amelia's behavior in verbal irony. George is no hero, and Thackeray takes up the entire situation as a bitter satire of the ways that marriages fall into dysfunction without accountability.
In Chapter 49, Lord Steyne beats back accusations of Becky's impropriety as his social circle catches wind of the possible affair between the two. Thackeray emphasizes the passion behind Steyne's defense through the use of hyperbole and metaphor:
As for Mrs Crawley’s character, I shan’t demean myself or that most spotless and perfectly irreprochable lady, by even hinting that it requires a defence. You will be pleased to receive her with the utmost cordiality, as you will receive all persons whom I present in this house. This house?’ He broke out with a laugh. ‘Who is the master of it? and what is it? This Temple of Virtue belongs to me. And if I invite all Newgate or all Bedlam here, by — they shall be welcome.’
Lord Steyne's support for Becky hinges on the hyperbolic assertion that she is "spotless" and "irreproachable" and apparently perfect—a fountain of dramatic irony for the reader, who is well aware of Becky's duplicitous and manipulative behavior, of which London society is only beginning to grow suspicious. Steyne then issues a metaphorical comparison between his house and a "Temple of Virtue" over which he has absolute power, like some sort of despotic priest. Steyne's insistence on his virtue—and the supposed virtues of his consort—only serves to underscore his deep vanity.
