Marinette is a sweet, outgoing and joyful girl. Despite her outgoing and empathetic personality, Marinette struggles with self-confidence and self-esteem. She used to be even more very nervous and didn't oppose others, but her confidence grew considerably since she became Ladybug. In a situation, she deems urgent, she becomes very nervous, clumsy, a bit awkward, and quick to panic. These situations include approaching her crush, trouble-choosing between her love interests, when in contact with a really big celebrity if she thinks others do greater success compared to herself or losing something that will expose her secret identity. Thanks to her confidence as Ladybug though, Marinette has gotten more calm and comfortable around Adrien as herself, as seen when she helps him get away from a swarm of fans and talks to him more fluently. 

Description provided by the Miraculous Ladybug Wiki.