The most-requested Sweetheart candy saying is "Marry Me," according to Necco Candy's director of marketing. "Be Mine," "Be True" and "Kiss Me" have been popular since the candies first appeared in 1902.
Necco updates the candy heart sayings each year, retiring sayings that are no longer in vogue while adding new ones. In 2010, Necco surveyed the public online for new Sweetheart sayings, accepting the most popular out of over 10,000 submissions. Sayings like "Tweet Me," "Love Bug" and "You Rock" appeared recently. Retired sayings are either phrases no longer in use, such as "Oh You Kid" or "Groovy," or phrases like "You Are Gay" that have changed meaning considerably over the years.
Candy printing technology plays a large part in what sayings appear. In the 1800s, the candies were much larger than the later version, which allowed for longer phrases. With the introduction of the small heart shape in 1902, the candy did not have room for many words. A stamp-like press prints messages using vegetable dye ink, which also limits phrases. "Pucker Up" was tested, but the stamps did not reliably produce a closed "P" shape.