Would you say 'I love This Guy to the level of being my intimate lover without knowing anything about him'?
I think that Aerith was saying, "I love this guy to the level of being my intimate lover while acknowledging that there's more to him that I still haven't figured out yet."
Aerith's feelings for Cloud started from his similarities to Zack and built up on that. By the end of her life, she had started to build up her feelings for him away/apart from his similarites to Zack. Meaning that, where she had pursued the similarities before, she was later starting to seek out the differences. However, even the parts of real Cloud that she may have glimpsed during their interactions with one another were not entirely separate from the Zack-Cloud person that she knew. So ultimately she was in love with the Cloud she knew, the Zack-Cloud person, the one who's at the same time like Zack and isn't.
I mean, certainly, they never had any conversations of just!Cloud and Aerith, but the Ultimanias mention her knowing that something isn't right and knowing what he's like on the inside.
I thought the Ultimania said that she saw through the facade, but it didn't say that she knew what he was like on the inside.
Personally, I'd always thought she had caught on that he was putting on an act or a front, but her seeing through that facade was only to the extent that she knew there was more to him that hadn't been revealed to her yet. That's why she said she wanted to meet the real him.