Tyrant or Lover

Boukun, Arui wa Dekiai
暴君、あるいは溺愛

Source

Tyrant or Lover
Cool na Shachou no Dekiai Sengen!?· クールな社長の溺愛宣言!?
novel

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