"Not again" was likely a reference to his dead wife which of course caused him to turn more strict.
@omegal0l
The Duke never hated his daughter, you can tell by the going shopping and talking about a suitable spouse before passing out.
The Duke is one of those father's that suck at expressing themselves and terrible at speaking like Rebecca's father from "Pet of the Villainess"
That sword he gave the original was probably to defend herself or a sign of proof since "No weapons can enter" Yet a weapon entered.