"That’s why he’s chosen Draco, isn’t it?" she persisted.
The odd chill that had lain over Privet Drive for two weeks persisted here too.
"But it sounds like it was invented while you were at school," Harry persisted.
Harry persisted in the common room that evening, but his assertion that the whole team would be devastated if Ron left was somewhat undermined by the fact that the rest of the team was sitting in a huddle in a distant corner, clearly muttering about Ron and casting him nasty looks.
There are no more uses of "persist" in the book.
Show samples from other sources
The child persisted in asking questions despite my obvious desire to be left alone.
We expect the conditions to persist into next year.