Shiratori, Urara

Urara has a slightly prideful attitude, due to her seemingly wealthy background. She considers herself an adult and to justify her claims, she tried to imitate "adult things" by using cosmetics, believing that games are "child-stuff" and generally acting mature. However, when she was hit by Keima, she reverted back to her childish self and cried. It was shown that Urara only pretends to be mature and would be more childish when she's not with her peers.

(Source: Kami nomi zo Shiru Sekai Wikia)