You shouldn't lie about things to people.
While Marry and Shelly are shopping for dresses, Shelly picks an ill-fitting dress commenting how much she loves it.
Marry wants to respond to Shelly.
Marry tells Shelly the dress doesn't suit her suggesting something else instead.
Marry tells Shelly that the dress is fine.
Shelly goes on her date, and her date thinks she looks amazing.
Shelly goes on a date, and her date teases her about her dress making Shelly sad.