Daisy's reputation is part of the illusion created in the novel. In her world, appearances are everything, and Daisy perpetuates the myth of her pristine reputation and perfect life. She has money, is married to a man from an aristocratic family, and she has a beautiful child. For all intents and purposes, she seems to have the perfect life. Daisy seems to carry with her an aura of charm, sophistication, and grace. The most important thing to Daisy is to maintain this myth. We all know, however, that appearances can be deceiving.
In truth, Daisy is shallow and fickle, incapable of true love or loyalty. This is seen with her indifference to her own baby, who is at times a nuisance in Daisy's life. She is amoral, corrupted by money and what it can buy. She loves her life of ease and material luxury and will do anything to protect it. She proves this throughout the book. She chooses Tom over Gatsby, and then she allows Gatsby to take the blame for Myrtle Wilson's death even though she was driving the car. She doesn't even go to Gatsby's funeral.
Fitzgerald uses Daisy to represent the amoral values of East Egg and to show how money can corrupt those who value it above anything or anyone else.