Brothers’ War: Let’s Not Talk About Looks

[Female lead disguised as a man + outwardly cold, inwardly warm heroine + flirt + possibly multiple love interests + no cheating] On the day she was adopted, Asahina Sanae began pretending to be a boy, treating everyone in the family with coldness and distance. Her true identity wasn't revealed until her older sister arrived. “Just because someone is cute doesn't mean they're not a boy, right?” “Actually, Sanae is cuter than anyone.” [Also: Sorry if the characters are out of character!]