The Golden Rose is a minor object in the first Dark Parables game, Curse of Briar Rose. It is placed in the player's inventory once the main game is completed. In order to use the golden rose, the player must begin the game again in what is now "hard mode". It's a somewhat spoiler of the next game as it hints to one of the main characters.
While playing through for the second time, the player will now have something to place inside the golden vase next to the door at the bottom of the well. Once the golden rose is placed in the vase, the door will open and the player can access the Secret Room.