Instead of giving girls just flowers, you can give then things like bracelets and necklaces. Here is what you have to do: Take your hoe and go to the mines where you get copper, silver, minstrel, and gold. Instead of going into the actual mines just go into the very first room, where Flora normally is. Then take you hoe and use it like you would to plant crops. It might take a few tries but then you will find things such as bracelets and necklaces. Give them to the girl you want to marry and she will accept and like them.