"Of a sort. I'll give you this much: the information involves a person, though I am not asking about a person."

This is very legalese and rule lawyery. But he's technically right. After all, Strange is asking about a spell to raise someone from the dead, not the Ringmaster to raise someone from the dead herself. Besides, it's a fun game to be as cryptic as possible—he can see why the fae enjoy it.