The Non-Magical Otaku Lady is Enchanted by the Next Duke's Deep Devotion (20)

I won’t marry anyone but you. Caught between the overwhelming affection of the future duke and the obsession of a young genius wizard! ―Don’t think you can escape from me. Countess Alitzia is completely absorbed in bookkeeping and has no interest in socializing. Although her family worries about her marriage prospects, she is secretly in a relationship with Miroswaph, an elite nobleman studying at a foreign university. However, despite being a noble, Alitzia lacks magical power and confidence in whether she is a good match for Miroswaph, who is admired by all the young noblewomen in the country. Amidst all this, during a ball celebrating Miroswaph’s return from abroad, Alitzia is suddenly kidnapped by Kamil, a young genius wizard who crashes the event!