The Final Fantasy XIV Lodestone has been updated with a lore piece about the in-game celebration called "Valentione's Day". In addition to the lore behind the celebration, players are given specific information about how and where to participate in the event scheduled to run from February 1st through February 15th.
The heart-shaped escutcheon used in her house's coat-of-arms was added after the death of Countess Arabelle, in remembrance of the similarly shaped shield she oft carried into battle.
As Valentione's Day became more popular, the story of Countess Arabelle and her crimson shield became more and more widespread, in turn, transforming the shield into a symbol of fortune and happiness. Two centuries ago, the Culinarians' Guild was finally successful in obtaining permission from the House Valentione to use a representation of the coat-of-arms on their festive chocolates.
Read more here.