Ron Supports Harry's Use of The Half-Blood Prince Despite the Sectumsempra Incident
Pages 539-540
After Hermione leaves, Ron Weasley reassures Harry that he's not crazy for wanting The Half-Blood Prince back. He reminds Harry that the Prince's bezoar tip saved his life, and while Sectumsempra was a dangerous spell, Malfoy healed quickly. Despite Ron's support, Harry still feels guilty about the spell and continues to suffer through his detentions with Snape.
