There are three girls to choose from in this game, and marriage is a requirement! However, the way you go about courtship and marriage is quite different...
For one, marriage is required in this game. Since child-rearing is an important factor in later chapters, you have to get married! Although you can propose to a girl early on, you cannot get married until the end of chapter 1. (The first day of spring in the second year.)
Second, no home extensions are required!! When chapter 2 starts your house will have a kitchen, and you didn't have to pay for it. Maybe Takakura figured that you would need a bigger house and paid for it himself or something... Your home is enlarged again in chapters 3 and 4.
In order to get engaged, you must meet the following requirements:
-Gotten a girl up to four red hearts (check her diary)
-Gotten a Blue Feather from Flak
You do not have to give the Blue Feather to the girl before the end of winter in order to get married. If you go all the way to the end of winter without giving the girl the feather, you'll probably end up marrying her anyway. You'll get an extra cutscene in which, well, the girl pretty much proposes to you...
Where she lives: Vesta's farm
Where she works: The same farm
Daily schedule (before marriage): It varies, but she gets up at 6AM most days, and goes to bed at around 9PM. She spends most of the day at Vesta's farm, either outside or in the house.
After marriage: Celia wakes up every morning at 6AM and goes to bed at 10PM. In chapter 2, she very rarely goes outside... she seems to stay in the house all day, alternating between the front room and the kitchen! In fact, during the two years of chapter 2, I only saw her leave the house three times... However, in the rest of the chapters, she does go outside quite a bit. Sometimes she will go to bed a bit late if she took a late evening walk outside or goes into your child's room in the evening. She rarely stays up past 10:30, though.
Celia is very cheerful, friendly, sometimes a bit childish, and obsessed with plants. She and Vesta are very close, and Vesta even says at one point that she thinks of Celia as though she were her own daughter. The more you befriend Celia, the better of friends you'll become with Vesta. However, if you become good friends with them, chances are that Marlin, Vesta's brother, will get jealous... so, beware!
Likes: Flowers, moon ores and coins from the ruins, vegetables, eggs
Really Hates: No matter how good of friends you are with her, in chapter 1, if you show her the Blue Feather and then tell her she can't have it (option 2), this will seriously damage your friendship with her. So be careful not to tease her in this manner if you want to be her friend.
Diary: Celia's diary is located in her room in the attic of the house on the produce farm. Check her bed, it's under her mattress.
Where she lives: The Inner Inn
Where she works: She has no job
Daily schedule (before marriage): One word: random. She wakes up at a different time each day (though 9AM seems to be a favorite with her) and can be found almost anywhere in the valley. However, she can be found near the mansion, near the produce farm, and in the bar a lot, so look in those places first. Some days she will go to bed very early, but other days she stays up quite late and may not get any sleep at all. She tends to sleep in long shifts, too: her record for me so far is 17 in-game hours!
After marriage: She gets up every day at 7AM, and normally goes to bed at 10PM, though she stays up later when she goes to the bar. She leaves the house a lot, and sometimes goes up to Mineral Town, but most of the time, she hangs around the farm, bar, or the spring, so it's not too hard to find her.
Nami is very different from Muffy and Celia. She might seem very cold and indifferent toward others, but she's merely hiding her real feelings. She's very smart, but has trouble relating to other people. She'll open up to you a lot more if you marry her, and will become more cheerful, too. Tim and Ruby think of Nami as their own daughter, so befriending her will mean that you befriend them, as well. After you're married to her, they love it if you show your child to them. Tim wishes that Rock had been more like him at that age... Needless to say, Rock might not be too fond of your child for a while...
Likes: Clay artifacts and fossilized skulls from the ruins, your home cooking, flowers that grow in fall
Dislikes: Any other kind of flower, minerals
Really hates: Dishes that didn't come out right
Diary: Her diary is in her room at the inn, near the window.
Where she lives: The Blue Bar
Where she works: The bar
Daily schedule (before marriage): She wakes up at 10AM, and can be found in the room adjoining the bar. On days that she has to work, she'll be behind the counter around noon or one PM. On days that she doesn't work, she'll leave the bar and go for a long, long walk. You cannot give her anything while she's working, so make sure to give her a gift in the morning!
After marriage: Muffy wakes up every day at 8AM and generally goes to bed at 11PM, though on nights that she goes for a walk or goes to the bar, she will go to bed later. She does leave the house quite a bit, but never goes very far.
Muffy is generally quite cheerful, fairly clumsy, and somewhat flirty. It might take a little while to gain her trust, though. She's apparently been hurt by so-called friends in the past... She and Griffin are very close friends, and befriending Muffy means you'll befriend him, as well.
Likes: Flowers (especially the Amorous flowers that grow in winter), sweets, coins and Moon Ores you find the the ruins. After marriage, she will only accept your home cooking, Amorous flowers, Moon Ores, and coins.
Dislikes: Fossils from the ruins, colombo fish
Diary: Muffy's diary is in the bar, in the potted plant in the corner.