He's never met her, and probably never will; replicas never live long, not as long as the original still lives.
But when traversing through the memory-worlds crafted by Naminé, he sees her - a simple vestige, an apparition created from the memories of the Keybearer. Cropped auburn hair, eyes a livelier mirror of those possessed by Naminé, and a smile to outshine Kingdom Hearts itself.
But she's gone in a heartbeat (of the heart he doesn't really have).
Even so, he had never been so in love in all of his brief life.