In Chapter 13 , the narrator uses an oxymoron to describe Lady Russell's thoughts when Anne mentions Captain Wentworth's romantic attachment to Louisa Musgrove:
Lady Russell had only to listen composedly, and wish them happy, but internally her heart revelled in angry pleasure, in pleased contempt, that the man who at twenty-three had seemed to understand somewhat of the value of an Anne Elliot, should, eight years afterwards, be charmed by a Louisa Musgrove.
Although Lady Russell responds to Anne's news with composure and well-wishes, in reality, she feels both angry and pleased. The presence of these two seemingly contradictory feelings is an example of oxymoron. Lady Russell, who feels protective of Anne, persuaded Anne eight years prior to break off her engagement with Captain Wentworth, who she believed to be unsuitable because he had neither fortune nor rank. Despite this, Lady Russell responds negatively (that is, she feels angry) when she hears news of his interest in someone other than Anne. Lady Russell looks down upon him, which confirms her negative view of him. This causes Lady Russell to feel a sense of pleasure, making her feel justified in her original estimation of Captain Wentworth. This complicates Lady Russell's nature, revealing a flaw. All in all, her intentions, and even reactions, are not always as unbiased as they seem.
In Chapter 23, the narrator uses an oxymoron to describe the intensity of Anne's emotional state as she reflects on her conversation with Mrs. Smith and her romantic feelings for Captain Wentworth, feeling a wave of emotions as she thinks about the entire situation:
She was deep in the happiness of such misery, or the misery of such happiness, instantly.
Anne feels both unhappy and happy at the same time, two emotions that seem to contradict each other. In juxtaposing happiness and misery, two things that are considered opposite from each other, Austen reveals a deeper truth that unhappiness and happiness can exist at the same time. Or, more specifically, the novel subtly implies that there's a direct link between unhappiness and happiness—it's not just that they can exist simultaneously, but that there's sometimes something strangely pleasurable about romantic misery, as if a feeling of sorrow or unrealized longing is simply part of the otherwise rewarding experience of being in love. Happiness, after all, cannot exist without sorrow, since it wouldn't mean anything in that case. Anne's tumultuous emotions surrounding her feelings for Captain Wentworth are therefore faintly pleasurable, since they're part of the broader experience of being in love—even if they're also rather torturous.