Yes it is a sign of purity and chastity. That's the simple answer. If you seek a more thorough answer you should seek out a parent or any adult whom you know and trust.
White reflects purity, innocence, and a virginity. By tradition a bride is to be wholesome, and during her first consummation with her newly wed husband, she loses her virginity. And typically it was reserved for the bride, so no attention was deviated from her.
Chastity means abstinence from sexual intercourse (purity).
Innocence and purity
Lucy represents chastity and purity.
Staying away from sex till marriage
Purity / Virginity
Chastity and purity were virtues of Saint Lucy.
Chastity is a vow of sorts, most likely meaning the vow of virginity, and to protect that would mean to protect her vow of virginity, or innocence.
Well, basically a purity ring means that you are not going to loose your virginity before mariage.
There is no question of Hala or Haram in the case of Valentine. Anyhow, the Muslims should avoid celebration of such events as have no base in Islam. Adopting the culture of Christians is not appreciated in Islam. Islam teaches chastity and purity. Any action that is against morality, chastity and purity is not liked by Almighty Allah. Any action that favours/strenghtens morality, chastity and purity among the Jews or the Christians is Islamic in nature. I am sure you know that Valentine does not promote chastity.
Chastity is the state of purity, free from impure thoughts and actions. Celibacy is the state of not being married.
The Lily symbolizes the virgin Mary for purity, and lily of chastity might be also referred to the lily of purity which is another name of the virgin Mary. chastity is a sexual behavior accepted in a civilization. Sometimes related to woman waiting to have sexual intercourse only after marriage. Chaste in Latin means pure.