Laura

“An Unbreakable Vow?" said Ron, looking stunned. "Nah, he can’t have.... Are you sure?"
"Yes I’m sure," said Harry. "Why, what does it mean?"
"Well, you can’t break an Unbreakable Vow..."
"I’d worked that much out for myself, funnily enough.”
― J.K. Rowling, Harry Potter and the Half-Blood Prince

“And what will you give me in return, Severus?’
‘In – in return?’ Snape gaped at Dumbledore, and Harry expected him to protest, but after a long moment he said, ‘Anything...”
― J.K. Rowling, Harry Potter and the Deathly Hallows

“Mr. Moony presents his compliments to Professor Snape, and begs him to keep his abnormally large nose out of other people's business.
Mr. Prongs agrees with Mr. Moony, and would like to add that Professor Snape is an ugly git.
Mr. Padfoot would like to register his astonishment that an idiot like that ever became a professor.
Mr. Wormtail bids Professor Snape good day, and advises him to wash his hair, the slimeball.”
― J.K. Rowling, Harry Potter and the Prisoner of Azkaban

“Karkaroff intends to flee if the Mark burns."
"Does he?" said Dumbledore softly, as Fleur Delacour and Roger Davies came giggling in from the grounds. "And are you tempted to join him?"
"No," said Snape, his black eyes on Fleur's and Roger's retreating figures. "I am not such a coward."
"No," agreed Dumbledore. You are a braver man by far than Igot Karkaroff. You know, I sometimes think we Sort too soon..."
He walked away, leaving Snape looking stricken.”
― J.K. Rowling, Harry Potter and the Deathly Hallows