Of course the stage is set for ML to think MC's sister as her. Now where have I seen that plot before?
This one probably
https://www.mangago.zone/read-manga/i_grabbed_the_leash_of_the_blind_beast/
MC also took care of blind ML and purposely lied about her appearance. Granted story is different but both have the same trope.
What's the point of ch 45 if ch 44 is not available?