The scene when Noon tried to drive away and thought that she hit Paul so she came out to look and Paul grab her and said that she's mean. He asked her "what if you hit me and I died, what would u do" and she said she'd put money in an envelop to help with his funeral. They agrued and he said that she's getting crazier each day with her revenge so he threw her in the pond to cool her down and maybe she'll get some sense back.
When Paul and Noon returned home, Paul's mom and the n'rai accused Noon of taking Paul away so she can have him to herself. Paul protected Noon and told them that she didn't make him go with her but he was the one that took her away because he wanted to and it's normal for them to go away overnight together because they're husband and wife. Then he said they were tired and wanted to rest so he put his arms around Noon, called her "teerak" and went into the house. That's why the mom and n'rai were shocked.
Inside the house, Paul and Noon talked about what happened b/w them. Paul said he's going to take responsiblity for what happened and Noon said it's not necessary but Paul insisted. He said that he can distinguish b/w revenge and responsiblity (though he wanted to say love). He continued to say "from now on, I'm going to forget about the password and live with u as ur husband not the son of the guy u're seeking revenge. As for what you'll do is up to you."
In Paul's conversation with the maid, he asked the maid about the day his mom made Noon do all the chores, what all happened. The maid explained to him everything and said that Noon never had to do all those things, that her parents always took care of her and never let her be alone so if her parents were still alive, she wouldn't have to endure all this hardship.
I hope that helps u to understand the lakorn a bit more.