I'm Marrying the Pauper Count of a Remote Frontier, So I'll Work Hard to Reform his Territory ~The Letter From Boule~

Henkyou no Binbou Hakushaku ni Totsugu Koto ni Natta no de Ryouchi Kaikaku ni Hagemimasu

Falsely accused of a crime she didn't commit, Angelique is cast aside by the second prince. The cherry on top? Now she has to marry a poor count in a remote parcel of the kingdom. What she finds there is shocking: abject poverty and a strikingly handsome count?!

(Source: MangaPlaza)