Sweethearts are small heart-shaped candies sold around Valentine's Day. Each heart is printed with a message such as "Be Mine", "Kiss Me", "Call Me", and "Miss You". Sweethearts are made by the New England Confectionery Company, or Necco. A similar type of candy is sold in the UK under the name Love Hearts. Necco manufactures nearly 8 billion sweethearts a year.
Sweethearts are now available in a variety of assortments to choose from including chocolate, tart, and smoothie flavors.
Daniel Chase, brother of Necco founder Oliver Kasey Chase, began printing sayings on the candy in the 1860s. He designed a machine that was able to press on the candy similar to a stamp. The candy was often used for weddings since the candies had witty saying such as: "Married in pink, he will take a drink", "Married in White, you have chosen right", and "Married in Satin, Love will not be lasting".
Sweethearts got their start in 1902 and an original box can be found in a Glasgow office on Sauchiehall Street. Back then, they were not only hearts but postcards, horseshoes, watches, and baseballs. Some of the sayings, such as "Be Mine", "Kiss Me", and "Be True", are still in use. In 1997, the saying "The One I Love" was brought back in honor of Necco's 150th anniversary.
In the 1990s, Necco vice-president, Walter Marshall, wanted to update some of the sayings and retire others. Necco receives hundreds of suggestions a year on new sayings, including "Call me", "Email me", and "Fax me".
Necco still uses the same formula to produce the candies. The recipe includes sugar, corn syrup, gelatin, gums, colorings, and flavorings. The recipe is brought to a consistency of a dough, rolled out, imprinted with sayings, stamped into a heart shape, and then put through a 45 minute drying cycle for consistency.
Necco produces the hearts from late February though mid January of the following year. Approximately 100,000 pounds of hearts are made per day, which sells out in about six weeks. 
In the classic book Anne of Green Gables, published in 1908, Gilbert attempts to give a pink candy heart with the words "You Are Sweet" to Anne, who promptly grinds it under her heel.