Fandom: Buffy the Vampire Slayer
Disclaimer: Not mine.
Ben was a good man. Giles knows that. And the Slayer was fond of him, to the point that she might have risked the end of the world in the desperate hope of finding another way to rid them of Glory.
But Giles also knows that Ben, through no fault of his own, was dangerous, and that the Slayer's friendship would not have saved him, or any of them, if Glory had had her way.
The truth, however, would destroy the last of Buffy's innocence, and her trust in Giles with it. She can never know how Ben really died.