"Ron can laugh," said Luna serenely as Harry led her and Xenophilius toward their seats, "but my father has done a lot of research on Gernumbli magic."
The family looked quite happy and normal, smiling serenely up out of the newspaper.
Striping away the popular image of serene, silver-bearded wisdom, Rita Skeeter reveals the disturbed childhood, the lawless youth, the lifelong feuds, and the guilty secrets that Dumbledore carried to his grave, WHY was the man tipped to be the Minister of Magic content to remain a mere headmaster?
"No, it was definitely a Snorkack horn," said Luna serenely, "Daddy told me.
There are no more uses of "serene" in the book.
Show samples from other sources
While I lie awake worrying, she sleeps serenely.
She remained serene even when he was yelling at her.