Isshuu Mawatte Heroine desu! Jishou Akuyaku Reijou no Dekiai Keikaku ni Kyouryoku Shite, Risou no Danna-sama wo Teni Iremasu

Born into a poor baronial family, Lucia has managed to get by since childhood with much support from Rosalinde, a self-proclaimed "villainess." Thanks to Rosalinde, Lucia is able to enroll in a prestigious academy for the wealthy, but soon after starting, she gets caught up in Rosalinde's wildly delusional and complicated love life. Apparently, Rosalinde is a self-proclaimed "villainess," and even though she and the Crown Prince are clearly in love, she won't be satisfied unless she steals him from me? The Crown Prince, who dotes on Rosalinde, also wants me to be a scapegoat for the sake of their love... I'm so tired of this farce! Will she get a wonderful husband after being tossed around by a self-proclaimed villainess and a scheming Crown Prince? A romantic comedy about a poor young lady and the eccentric characters of the academy, with their schemes intertwined!

(Source: Kadokawa, translated)