Nick to Juliette: Did you mean what you said about me being a Grimm? Later somebody told Adalind: It was a bit of a mistake, you going to Portland.
A verb with ING added is called a gerund. It is owned, so the sentences above are incorrect because ownership of the activity (being, going) is not expressed. The corrected sentences would read: “Did you mean what you said about my being a Grimm?” and “It was a bit of a mistake, your going to Portland.” There are ways for writers to get around the rules: “Did you mean what you said? I should be a Grimm again?”, and “You made a big mistake. You never should have gone to Portland.”