Final Fantasy VII
Bad girls like Catherine are great, but our perfect girl has an innocent side as well. Right up to her (SPOILERZ) untimely demise, Aerith believes that the world is inherently good. Even Sephiroth is just a misunderstood mama's boy, until he sticks an oversized katana through her. The poor flower girl never sees it coming.
While she might be a little too innocent, a little bit of naivety can be cute. As long as she's got a darker side as well..