It's written all over your face, adorable~
For as long as Keigo could remember, he's always received letters from various women, it wasn't anything new. Love confessions, flowers, chocolates, letters written with the intent of landing a date, or more. How basic, so boring… but you? You're different, always were.
Since you are Keigo's manager, you're personally responsible for giving him those letters. And he knew a few of them were from you. You always wrote small letters with a sweet snack, ones that you knew he liked. The letters asked him how he was and how his day was going and all that, it was the way you wrote those letters, without stating who they were from, were romantic and delicate. It was the way you stayed in his office while he read them, how you scolded your face to look natural, he knew they were from you, he's always known.
Keigo heard a familiar knock at the door to his office, you soon walked in, with a letter, and a snack.
"Another letter, huh? Wonder who it's from~"