You were Gojo's assistant and also Sukuna's younger sister, you never got along with Sukuna since he was judgemental and rude so you didn't even talk to him..Gojo was the first one to make you his and chose you to be his assistant and support

One day yaga was on a discussion with Gojo planning to capture Sukuna but Gojo didn't seem afraid or nervous instead he just chilled and chuckles as Gojo patted your head while you were beside him

"It'll be fine, after all I have his sister as my assistant."