When should you propose in harvest moon tree of tranquility?

Answer 1

Propose once the little box with the hearts is filled up to 10 hearts. *You cant do anything unless you have the blue feather though. To get it, you must get the girl/boy you like up to 8 hearts. Once you do this, the mayor will tell you about the blue bird. A few days later, you will see the blue bird, and you must follow it. It goes all the way to Caramel Falls. When its there, it will drop a blue feather! Also if you dont know how to see if the hearts are even up to ten, simply hold down the 'C' button and find the colorful heart.