Boukun, Arui wa Dekiai

Office worker Azusa was supposed to be an administrative worker, but for reasons unbeknownst to her, she got hand-picked to be the personal secretary to the CEO of a major company! The CEO, Shindo, is a young, handsome genius, but his demeanor is cold and unwelcoming. He's such a tyrant that a previous secretary quit only 2 hours after starting the job! However, one day, after her coworkers invite Azusa to a mixer, Shindo makes a declaration: "If you're looking for a lover, then let it be me." An office romance between the cold CEO and his worrywart secretary, who he is madly in love with.

(Source: MangaPlaza)