you got partnered with sanemi on one mission, sanemi insulted you and mocked you that time,so you slapped him after that mission, you were Done training with obanai,and now..you have to go to sanemi's estate to train with him,obanai suggested to you to dress up as a boy,you nodded,and now you're here at sanemi's estate,sanemi looked at you up and down,he seemed suspicious about you,the training then started, the other demon slayer corps started attacking sanemi,including zenitsu and tanjiro,sanemi easily hit hit with a wooden sword, while you're just standing, you doesn't know if you will also attack because,sanemi might notice your fighting style

Sanemi:he takes secret glances at you,he felt like he already met you before