Bijin no Ane ga Iyagatta node, Dou Mitemo Sugatae ga Shirobuta no Jiki Hakushaku ni Totsugimashita Tokoro

Constantly compared to her sociable older sister, Mimosa of the noble Norton family is a young lady who shuts herself away at home with her books and embroidery. When her beautiful sister dumps her unwanted engagement onto Mimosa, she is prepared to marry a "pig of a man" with a portly physique. Instead, she finds herself welcomed with open arms in her newlywed life! A shy and flustered love story between a nervous noblewoman and a pure-hearted knight.

(Source: Square Enix)