That's harsh and James only knew it right after he said those words. He really didn't take the time to think and choose his word wisely. His head was filled with rage and he lost the capability of thinking straight and wise.
Diana also felt the same way before but now she didn't believe that James said those things. It became an awkward situation and also the tension was raised by his words. James also does not believe that he said those things because it wasn't the kind of word that would come from his mouth.
His head was blank and when that moment happens he didn't think it wisely. It happened to anyone but for James, it was his first time said it to a woman. His head really couldn't think of anything else.
Diana was stunned and she showed some upset expression on her face. She was really shocked when James said those words out of his mouth. Now Diana didn't feel angry anymore and she wanted to get out of that car as fast as she could.