explain and elaborate on this quote

Daisy IS Gatsby's dream...... or so he believes; she always has been. This quote obviously comes from an afternoon the two spent together in Nick's company. Nick's observation is that there must have been a few times during that afternoon when Daisy fell short of Gatsby's expectations. You have to remember, he's been gone a long time. The money, the house, the school, the books...... all of it was acquired for HER. Daisy isn't the woman he thought she'd be........ and Nick's assumption is that even for Gatsby...... the real Daisy must have fallen short of the illussion he'd been holding in his mind.