Moto Akuyaku Reijou to S-kyuu Boukensha no Honobono Machi Gurashi: Fuguu na Chara ni Tensei shite kedo, Risou no Bijo ni Nareta kara Plus Minus Zero da yo ne

"I'm pretty amazing, you know?" "With me, you'd be even more powerful." The pair that has it all have an S-rank adventure and romance! An isekai rom-com! Alicia is a haughty duchess who likes to cake her face with makeup. On the night before her banishment for bullying the heroine, Alicia remembers she is a villainess in an otome game... While feeling at a loss, she realizes something else. She has big breasts, good looks, and magical powers?! Who knew she was a triple threat! An idea dawned upon her, and she sought out her nerdy brother to be his assistant to research magical tools. Alicia displayed her talent and soon longed for a life of fun and freedom, rather than the strict upbringing of a queen. In the end, Alicia decides to live her life as a commoner... And she gets teased by the S-rank adventurer, Hayato?! An isekai rom-com with an S-rank adventure and romance!

(Source: MangaPlaza)