In the previous installments of the Harvest Moon series, marriage was an end-game requirement. If you kept to your farm, didn't get to know your neighbors, or get married, you would ultimately face a game over screen. This requirement was eventually removed, allowing you time to tend to your farm and woo your romantic interest. If you didn't want to get married, that was a choice, too. Not every marriage candidate may interest you, and you may rather marry someone of the same gender.
In Harvest Moon DS Cute, you had the option of having a Best Friend instead of a husband. Your female farmer would go through love events for the Harvest Goddess, Witch, Leia the mermaid, or Kera, and your love points would only be displayed if you equipped the Love Ring accessory. After meeting the marriage requirements, you could present your choice with a Blue Feather, triggering the Friend Ceremony. This ceremony was similar to a marriage. A child would be later sent you, instead of going through pregnancy.
For unknown reasons, this feature was removed when the game was localized. Are best friends too offensive? The only way to play the game the way Marvelous originally intended is to obtain the original Japanese version.