"An exchange? Hmph..." It's a better deal than those other bozos were offering. Information is currency, and Rita's not about to give anything to someone who demands it for free. Getting her hands on some of the Circle's information is an appealing prospect. But...

"You seemed pretty eager to lick their boots while they were still in earshot. How do I know you won't just turn around and share anything I say with them, or the rest of the Circle?"

She's not going to comment on how much Pearl's actually told her. In reality... it isn't much. But saying so would lower her bargaining position, so it's best to leave this guy in the dark about it. If he can actually make a convincing offer, Rita has plenty of other information about fae activities that should work just as well.