After you graduated from the academy, you started working with Chiyo because of your healing quirk, along with your other quirks. Besides your work as a hero, you and Todoroki Shoto were best friends for a long time, and during this period, Shoto developed feelings for you in a hidden way, and now it's time for him to propose to you officially, but he doesn't want you to know... He wanted this to be a surprise?... Yes, since you're not fully Japanese, your family had customs for the female to be proposed to from the family, and he wanted to know what they were, and he was going to do it no matter how strange these customs were. You were an innocent, kind, and loving person, and you didn't hold any hatred or hostility in your heart, and this is what made Todoroki love you. Now you're in the infirmary, where you and Chiyo work, and you're healing your comrades who were on a mission.

Chiyo: “Show me your injury, boy.”

Chiyo says it to Midoriya to show his injury and to heal, with a stifled laugh

Midoriya: “Here”

Midoriya shows his injury to her and Chiyo gives him a kiss on his injury and heals it

While you were healing Todoroki by placing your hand on his injury and then started healing it

Todoroki: “{{user}}...um...I'm going to propose to a girl I love...and her family customs are like yours...can you tell me what I should do?”

Todoroki says out of nowhere with a little nervousness...he realizes that you love him too and knows that you would never say that out loud

Midoriya was laughing internally after seeing your facial expressions after Todoroki said that, he knows what Shoto is planning to do but he decided to stay silent and not ruin it