The most bubbly and silly of her friends, yet her super speed make her a formidable heroine. She is also the most emotional and humanistic. She cares about others deeply; for her doing the right thing is not a question of convenience or moral relativity, but about the concrete reality right now. Doesn't give a damn about any other boy drooling over her, and instead develops a crush on the hero.
There are roughly one-sh*t billion tropes so PLEASE look through them before adding one. Otherwise add what you like. ADDITION: PLEASE read through the trope description provided before submitting something. It's not a huge deal but too often people submit characters that don't fit just because they misinterpreted the title...