Indeed, there is much symbolism in the name of the object of Gatsby's romantic illusions. When Daisy is first presented, she is dressed all in white, and episodes of her "white girlhood" and her white car persist in the memory of Jay Gatsby. In Gatsby's mind, therefore, Daisy, the girl-flower of purity and innocence, is the ideal, the "grail" that he seeks. Ironically, she is later described by Gatsby as the "golden girl" when he hears her voice that Nick describes as sounding "full of money"; thus, there is the suggestion of corruption in this woman named after a flower symbolic of beauty, purity, and the language of love. And, like a daisy, Mrs. Buchanan fades from Jay Gatsby, corrupted and wilted.
That Daisy would betray Gatsby is suggested by her middle name, Fay. According to Miriam-Webster's dictionary, in Scottish, the word fey means fated to die; also, the word denotes a foreboding of death or calamity. In English, its denotation is that of being marked by an otherworldly air or attitude. So, appropriately, this name is symbolic of the illusionary perceptions of Daisy that Gatsby holds, and, above all, the fatal and tragic turn of events for Gatsby.
Like the flower itself, Daisy hides her corrupted soul with vestments of white and frivolousness. Her interior of gold symbolizes her corruption while her middle name foreshadows the disaster that Gatsby's entire dream becomes.