Answer:
You first have to have a blue feather which you obtain from the sprites in your first year they will call you and tell you they found they found something. Once you have the blue feather you must first decide who you want to marry. After you decide that give them gifts they like so that you become better friends. After giving them gifts you can then give them the blue feather, if they except the blue feather then you become married if not you have to keep trying. I hope this has been some help to you :).