Why does nick think Daisys cynical outburst is fake?

Nick believes Daisy's cynical outburst is fake because it seems to be a façade masking her deeper feelings of vulnerability and dissatisfaction. Her dramatic tone and exaggerated expressions suggest that she is not genuinely expressing her true emotions but rather putting on a show to cope with her discontentment. Nick perceives that her cynicism is a defense mechanism, indicating that beneath her surface bravado, she is troubled and unhappy. This dissonance between her Words and her underlying reality leads Nick to view her outburst as insincere.