Final answer:
In "The Little Mermaid," Grimsby proposes arranging a royal meeting on Ariel's twenty-first birthday.
Step-by-step explanation:
On the eve of Ariel's twenty-first birthday in "The Little Mermaid," Grimsby proposes arranging a royal meeting. He suggests that Ariel should meet a suitable prince to potentially marry and secure her future as a princess. This idea sets the stage for the conflict and journey of Ariel's character within the story.