how does a girl act when she is raped then forced ot marry the rapist?

If you'd like, I can move this to the Character and plot realism forum, where you might get a more varied response.

sure that'd be great

This type of tale, while common, strongly annoys some people, for some pretty good reasons. Particularly if you're framing it as romance rather than Stockholm syndrome.

However, if it's "ravishment that she secretly desires" rather than brutal unwilling rape, then that's perfectly OK, and a standard staple of romance stories.

But normally, in real life, I suspect that if you were raped then forced by society to marry your rapist, (not uncommon in some cultures, even today), you'd expect to have to deal with a lot of depression and insecurity: you'd feel that nobody cared what happened to you, nobody was supporting or protecting you, and there was nowhere you could turn. You would withdraw from society, possibly spend long amounts of time doing something reclusive like throwing yourself into some project, or just curling into a ball.

Withdrawing from society like that, and giving up on ever finding someone to defend you, would make it easier for a malicious husband to abuse you any way he liked without repercussions. If he beat you, you would feel you deserved it.

But also, because of your isolation and very low self-worth, any small kindness shown to you by anyone, even him, will have a much greater effect on you than normal. If, while beating you, he tenderly wiped away your tears, you might take that for love. Then the rationalisations come. Perhaps he only beats you because he loves you. Perhaps, for his sake, so that he won't have to beat you, you should try to make him happier?

You could have a lot of fun getting into the head of such an abused spouse, male or female. Or, like I said, you could just go with the romantic ravishment staple.

My character has been raped then forced to live with his rapist. So far, he's locked himself in his room, tried to starve to death, escaped and had a panic attack and brought back by his attacker. Someone mentioned Stockholm Syndrome and my character has it. He's slowly falling in love with his rapist and now thinks he can't survive on his own. I've done a fair bit of research. Wikipedia is your friend. It's a dark place to go though. My mum was about to call a psychiatrist when I explained what was going on in my book!

I started writing a novel about the same thing, except the theme is about forgiveness and change.
If you need help describing the scenes, watching law & order special victims unit will help a lot; it did for me. Mine isn't about Stockholm Syndrome; the victim actually (eventually) falls in love with him.