The constraint is always raw material. She has no shortage of ideas or time in which to put them into practice. Hence, she is most avaricious in acquiring hearts whenever an opportunity presents itself. Having a stockpile means she need waste as little time as possible.
"I enjoy life, I must admit. The thrill of the hunt, the pleasure of fighting a clever opponent... And you are so very clever. A bit more practice, and you'll be terrifying."
"Would you like that? For people to flee before your heralds, for nations to tremble at your coming?"
"I want," she grits out, "to kill the man who forced this heart upon me."
"To put it simply: I'd like you to join my Hunt. You're good at what you do, and rather clever. I like your fire."
"Well, the name's still suitable. Your magic just relies on your own heart, now."
"You know, I don't think I heard an agreement or refusal for my offer. I won't kill you if you refuse, but, well, I suppose your life will be far more boring, on your own."
"If you turn your Hunt against the man who cursed me, then I'll join you."
"Of course. The full Hunt might not agree - we're hardly centralized - but I will Hunt him, and many will follow my banner for at least a time."