[ -- Aerith still hasn't told him she'd died- something Lightning pretty much knew already, but hearing that he's actually suspicious about something being hidden from him sharpens the frustration she feels due to her belief that he should be told.

She really wants to ask what he's noticed, but also realizes she can't take the risk of showing much more blatantly that she knows more than he does... because she won't be able to lie if he bothers to scout her for any clues. ]

I think you're right. If you're not insistent and don't ask her things directly, she'll just keep dodging forever. [ A pause; she doesn't really want to cast a bad light on Aerith, so... ] She doesn't... want people to worry.

[ ... That might be a clue too, though. ]