Osananajimi wa Mou Yameru

Since he was a child, Madoka has been in love with Tamaki. However, high school student Madoka is always regarded by college student Tamaki as a "cute younger childhood friend" and not as an object of romantic interest. As time goes by, Madoka graduates from high school and goes to the same university as Tamaki without telling him, and succeeds in renting an apartment next to his. Then, Madoka begins to make a fierce appeal to Tamaki.

(Source: Core Magazine, translated)