The phrase "she did grin to see his paper plaster" suggests:
* She found something funny or amusing: The paper plaster likely looked ridiculous or was a humorous situation.
* Her smile was genuine: Grinning implies a genuine expression of happiness or amusement.
Here are some possible scenarios that could explain the situation:
* He's a clumsy person: He might have gotten hurt in a silly way, and the plaster is a comical reminder of his mishap.
* The plaster is poorly applied: He might have tried to apply it himself, and it ended up looking messy and awkward.
* The plaster is a joke: He could have put on the plaster as a prank, and her reaction is one of playful amusement.
Ultimately, the meaning of "grinning" depends on the specific context of the story or situation.