A deliberate exaggeration, which no one takes literally, to give emphasis to a feeling or a situation.
In Madame Bovary
love, as she believed, had to arise suddenly, with great tumult and flashes [...] a storm from the heavens that falls on life and churns it up, tears wills away like leaves and carries the whole heart off into the abyss.
The love Emma awaits is described on a scale of catastrophe: "tumult," "flashes," a storm that "tears wills away like leaves" and carries off "the whole heart" into the abyss. No real affection goes that far, and the exaggeration shows the inflated ideal that books gave her.
Part II, Chapter 4, the narrator
Poor little woman! I'll bet she longs for love like a carp for water on the kitchen table! With three words of flattery, I'm sure she would even adore me!
Ah!, if, in the freshness of her beauty, before the defilement of marriage and the disillusion of adultery, she could have surrendered her life to some great and solid heart, then, with virtue, tenderness, sensual delights and duty blending into one, she would never have fallen from so lofty a happiness.
Part II, Chapter 15, the narrator
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