Mujikaku na Tensai Shoujo wa Kizukanai

Despite being a genius, the duke's daughter Liana is unable to earn her family's recognition. As such, she decides to run away. On her journey, she meets Fred, who seems to be just any other handsome adventurer. Sympathizing with her plight, he proposes they "become a couple"?! This is the tale of a genius girl seeking happiness, an isekai story of second chances!

(Source: Hakusensha, translated)