The Basics
Taylor Swift negates the tropes of fairy tales — and her own Love Story — by describing a relationship that left her disillusioned. Although her partner gets on his knees to beg for forgiveness, Swift chooses to leave, declaring “now it’s too late for you and your white horse to catch me.”
Literary Device: Litotes
Litotes is a type of ironic understatement that defines something by denying the contrary. In White Horse, Swift repeatedly uses litotes to describe herself and her story: “I’m not a princess”, “This ain’t a fairytale”, “I’m not the one you’ll sweep off her feet” and “This isn’t Hollywood.” Taylor Swift indirectly states how disappointing the relationship was by highlighting what it wasn’t: a fairytale or a Hollywood movie with a happy ending.
Analysis
Swift uses plenty of negative self-talk in White Horse, all related to her lack of knowledge: “Stupid girl, I should’ve known, I should’ve known”, “Maybe I was naive”, and “My mistake, I didn’t know.” The litotes in the chorus explain that Swift’s missing knowledge was a recognition of what this relationship is not: that she isn’t a princess, this ain’t a fairy tale, she’s not the one, and this isn’t Hollywood. In hindsight, Swift now describes her story with these absences of fairy tale characteristics rather than the presence of any characteristics, positive or negative. Swift has become a deconstructionist critic of the narrative she imagined in Love Story. After Swift erases her fairy tale description of the relationship, she does not reconstruct a new narrative around the relationship. Instead, she leaves nothing: the absence of a fairy tale, the absence of meaning.
Swift doesn’t define what this story is, but she describes what it is not, and that is enough to justify ending it. When Swift’s not-prince gets down on his knees and begs her to stay, it becomes clear that Swift is not the dumpee, but the dumper: “And there you are on your knees / Begging for forgiveness, begging for me / … But I’m so sorry.” Then, Swift subtly shifts the language in the third chorus to state “I’m not your princess” and “this ain’t our fairy tale” to make them no longer statements of disappointment, but assertions that she is leaving. Swift goes on to positively state “I’m gonna find someone someday who might actually treat me well.” She then finally shatters the quaint, fairy-tale imagery ubiquitous throughout the song by referencing her “rear-view mirror” as she drives off, leaving this story behind. Taken in this light, Swift’s litotes about herself take on a powerful new significance. She’s now “not a princess” and “not the one you’ll sweep off her feet” because she isn’t a damsel in distress waiting to be rescued, she is the one making an active decision to end this relationship and set off on a quest to find a new one.
Swift’s deconstruction of Love Story didn’t restate the meaning of the relationship, it erased that meaning and left nothing in its place. The opposite of Swift’s Love Story isn’t tragedy or a passionate song like Picture to Burn or Should’ve Said No, it’s disillusionment: mundane disappointment in what could have been. In contrast, Swift’s deconstruction of herself as protagonist allows new meaning to arise in place of her previous understanding. Swift tears down the image of a princess waiting for her prince to “come around” and replaces it with an image of a woman in a car too fast for a white horse to “catch.”
I think you define the whole song in way as a Litotes she is "defining something (herself) by denying the contrary (what she previously was, especially in relationship to him)".