No, there was no hypno app involved or anything like that. Kitaoji is a member of a very specific tomboy trope seen in Japanese media, as the translated title "Prince-like girl" alludes to. Put simply her personality fills the common aspects of that trope and you see her acting dashing, confident, and assertive. This type of tomboy usually tries to emulate a fairy tale prince that you would think of in a medieval fantasy setting.
Art 7. Plot 5. Sexiness 5. Translation 5. All out of 10.