Game of Thrones Season 6 Episode 06 Blood of My Blood
Jaqen H’ghar gives the Waif permission to kill Arya, on the condition that Arya doesn’t suffer. Meanwhile, Arya retrieves Needle from the rocks where she had hidden it and takes it to her room.
JAQEN H’GHAR: And?
THE WAIF: As I expected.
JAQEN H’GHAR: A shame. A girl had many gifts.
THE WAIF: You promised me.
JAQEN H’GHAR: Don’t let her suffer.
Source text: Wikipedia.