I’m the Villainess, So I’m Taming the Final Boss (2018)

Blurb:
Avoid the bad ending at all costs! When her fiancé breaks up with her in front of the entire student body, noblewoman Aileen d’Autriche is devastated – or she would have been, if that wasn’t also the exact moment memories of her past life came crashing back! Turns out, she’s been reborn as the villainess of a dating sim …and according to the story, she’s slated to die at the hands of the demon king in three months! But Aileen’s already got a plan: Step one, get Demon King Claude to fall in love with her. Step two, live!

Source: www.anisearch.com/manga/48682

宣伝文句
破滅フラグ回避を目指す悪役令嬢の、一発逆転ラスボス攻略スタート！
公爵令嬢アイリーンは転生前の記憶を取り戻したものの、自らが破滅まっしぐらなことに気づいて大ピンチ！！アイリーンが起死回生の一手として選んだ手段は、ラスボスの魔王クロード攻略？！

Source: www.anisearch.com/manga/48682