When you complete her romance and she moves in her outfit does change to a whiter outfit, if memory serves correct. Didn't you have an option to turn her down when she went to your house? It's /hard/ to romance Isabela, as she's extremely against love. And, Isabela won't ever move in with you. There are romance guides for Isabela, you need to give her all of her gifts to finish Isabela's romance quest I think.
i believe you are correct, Merrill is one of the easiest to get to fall for you, but if you falt out chose to turn her down when she shows up at your house, the image evan has a broken heart to it when you pick the option, that will end any chance of a relationship with her at that point.
You must have not turned her down, i have played twice already and turned her down no problem, my third time i am going for her though
on an additinal point, once you have isabela romantasized, the conversation she has with the group are entertaining to listen to then they pop up
[Edited by NarutoU, 3/18/2011 12:14:02 PM]