The color white on a character can symbolize innocence and purity.
Note: Should I just limit this to "white = virginity" for now, just to solve a few issues presented?
Whenever a character (often a young girl) is meant to be pure (usually as a virgin) and innocent (usually having a sweet, if naive, nature), and that character is largely wearing the color white (although other colors can be included, especially if they also symbolize purity). This is because in some cultures, the color is symbolic of purity. So wearing white often was meant to show at least the inherent purity of a person. This is why European kingdoms decided that winter white ermine should be the fur of royalty, why before Pink Girl Blue Boy kicked in, children of both sexes used to be dressed in white, since Children Are Innocent, why one of the most common form of Good Colors Evil Colors is white for the heroes and black for the villains, and why Unicorns and Angels are often shown in white. And showing white suddenly splashed with another color can also symbolize loss of innocence, such as with a Blood Splattered Wedding Dress. This is much rarer today than it used to be, but it's not quite as Discredited Trope levels. This frequently overlaps with Woman In White (if it's meant to be an innocent lady instead of just mysterious), Princess Classic (especially before Princesses Prefer Pink became a trope), Mysterious Waif. It less often overlaps with White Haired Pretty Girl and Man In White, but rarely overlaps with Winter Royal Lady (since wearing white for her is usually about being mysterious). A Sub Trope of Color Motif. A Super Trope to Fairytale Wedding Dress (since most are still white, for the reasons of this trope), White Magician Girl (since such characters are usually innocent). A Sister Trope to Gold And White Are Divine, True Blue Femininity (and a lot of innocent girls are shown wearing white and blue), Heavenly Blue, Shining Goodness, The Ingenue. Compare Pink Means Feminine, Graceful Ladies Like Purple, Hair Of Gold. Contrast Light Is Not Good, Lady In Red, Woman In Black. No listing aversions, please.