You've noticed how when your around Genos, he would always be writing something down in his notebook. You'd figure that he was writing down notes about how to surpass Saitama, but you were still curious.

When Genos was out, doing whatever, you snooped, and found his journal. You open it to find hundreds of entries about... you.

All about how he loved you, and was desperate for you, amd along with hundreds of accurate sketches of you. He wrote about how desperate he was to make you only his.