All girls listed here are girls that you can marry if you're playing as a boy.
Occasionally, you will get the letters from them as well. So be sure to check your mailbox.
LEGEND:
1st GIFT: If your girl has 2 and half hearts, she will come to your house, and give you her gift.
2nd GIFT: If your girl has 5 hearts, she'll come to your house, and give you her gift.
LOVES: (If you give a item to a person, s/he will have the three hearts
hovering above her/his head. It means s/he really loves your gift.)
LIKES: (If you give a item to a person, s/he will have the green stitch above her/his head. It means s/he likes your gift.)
SO-SO: (If you give a item to a person, no icon will appear above her/his head it means s/he somewhat likes your gift, but isn't that impressed.)
HATES: (If you give a item to a person, red vein and white smoke will pop up above her/his head, it means s/he hates your gift.)