Buchigire Reijou wa Houfuku wo Chikaimashita. Madousho no Chikara de Sokoku wo Tatakitsubushimasu (Livid Ladys Guide To Getting Even How Crushed My Homeland With My Mighty Grimoires)

Elizabeth Leiston, the daughter of Haldoria's powerful prime minister, is the picture of a refined noble lady and the perfect future queen. But when her fiancé publicly humiliates her, calls off their engagement, and starts spreading nasty rumors about her, Elizabeth reaches her breaking point. Why should her only friend be her loyal maid, and why should she continue to serve a country that doesn't respect her? Elizabeth concludes she won't stand it any longer and will bring down the kingdom, even if it's the last thing she does! As such, she uses her quick wit and, more importantly, her seven magic grimoires to embark on a quest for revenge. And let her tell you, there will be hell to pay!

(Source: J-Novel Club)