She does kind of insist Cloud tells the story. But then she probably does have hazy memories of Cloud saving her in the reactor. And Cloud has detailed memories of everything that happened - what was said, the photo, the bridge collapsing, Tifa's letter etc. - so how the hell does he know all this if he wasn't telling the truth? She probably thinks her own memories are sort of messed up after being nearly killed by Sephiroth.