Reginald was struggling not to show his fangs that were already itching to bite the human King for assuming that he could set him up with any of his daughters.
Reginald wanted Adeline, and Adeline only.
And as Dragomir was going on and on without even caring to pause and let Reginald express if he was interested to see any of his other daughters or not, Reginald finally lost his cool.
Reginald dug his nails in his palm and thought, "Why is this old fool trying to convince me to marry his other daughters rather than convincing Princess Adeline to marry me? Isn't marrying me more beneficial than marrying some nameless and title-less man who is clearly after the throne?"
And since both father and daughter seemed to be spellbound by that nameless man, he assumed that the nameless man had asked some dark sorcerer to perform some kind of spell on them.