So basically the uke has to marry the seme because his sister ran away, so since him and his sister look alike uke pretends to be her, not knowing that the seme already knows and that he was involved in his sister running away with her servant.
Is this it? https://www.mangago.zone/read-manga/lala_no_kekkon/
Yes omdsss thank uuu soo muchhhhヾ(☆▽☆)
No problemo (๑•ㅂ•)و✧
So basically the uke has to marry the seme because his sister ran away, so since him and his sister look alike uke pretends to be her, not knowing that the seme already knows and that he was involved in his sister running away with her servant.