"So this is where you live? Oh, Mother will love it up here!"
Frances says this to Robie when she discovers that he is quite wealthy and has an incredible estate home. Her statement is twofold. First, it shows that her mother finds it important to have wealth in society for her daughter and secondly that Frances' mother will be coming to live with the couple. An idea that does not thrill Robie one bit.
"Are you sure you were talking about water skis? From where I sat it looked as though you were conjugating some irregular verbs."
After Robie was talking with Danielle on the platform in the ocean Frances calls him out on his lie about their conversation's content. He told her they were discussing water skis but it was clear to Frances that they were speaking in a way that looked like attraction. Her use of "irregular verbs" speaks to her intelligence, wit and class. As Robie can't put one by her like most women, she's sharp to not use vulgar words to make her point and she doesn't throw a fit about it she simply engages directly with the man.
"Germaine has very sensitive hands and an exceedingly light touch. She strangled a German general - without a sound."
Robie says this to Hughson who is having breakfast at Robie's estate and compliments the food. Robie responds with this statement as a way to distinguish the type of person he is vs. the formalism of Hughson's British roots. It's a tactic he is using in negotiating with the man.