Jirekoi, Hajimemashita. Kimi to Watashi de, Koi ni Naru made

Chihiro, twenty-five-old, is madly in love with her colleague, Nakaba. He's cool, clever and handsome. They go for a drink almost every day, so she knows that he likes her too. However, she can't ask him to go out with her, since part of her thinks she's happy the way they are. One day, her good friend tells her that she should tell Nakaba right away that she loves him, or else he'll be some other girl's boyfriend. Chihiro decides to tell him, but she's got a big project to handle in front of her... Can they become lovers? (Source: MangaPlaza)