Ie-Shoku Aikyou-Nashidesuga, Osananajimi Hakushaku ni Hiroware Amayakasaretemasu

Mia loses her home and job in one fell swoop after being falsely accused by her comrades in the knight order. The reason given? She lacks "charm." But Mia has always had a naturally stiff expression and can't smile easily, no matter how hard she tries. She had hoped that when she grew up, she would meet a wonderful person and build a happy family, just like the heroines in her beloved romance novels. Now, feeling lost and thinking, "Maybe I'll be alone forever," she is suddenly reunited with her childhood friend, whom she hadn't seen in years. He offers to let her stay with him, on the condition that she acts as his "guard." However, the title of guard is just for show—she somehow ends up being the one protected and doted on. https://www.cmoa.jp/title/349147/