This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Betrayal at Krondor
The ending. A lot of attention is given to the character arc of Gorath, his struggle to accept humans as potential allies and eventually friends, and his Tragic Dream of reforming his people to a more peaceful, prosperous and less starving and cutthroat existence. At the end, he's the one who has to give his life to save the whole world if not the whole multiverse from the return of the Valheru. When Delekhan tries to release them, Gorath stops him, but the Valheru start possessing them both. Upon hearing Pug say that the only way to save the world is to destroy both of them, and Owyn hesitating (not surprising for someone who has spent the entire story befriending him), Gorath shouts at him to do it. He is subsequently blown to smithereens. His dream of reforming the moredhel? That dies with him. The epilogue leaves the fate of the moredhel somewhat open, with Narab or the more reasonable Liallan fighting for leadership, but there's nothing to be optimistic about. The books in the series, at least, make it clear that the moredhel don't seem to have changed much even centuries after Betrayal. Gorath's death is made worse by the fact that he had previously Returned, aka undergone a spiritual transformation to an eledhel, which means that his exile and traitor status are no longer an issue and that he does have a place to go and happily spend the rest of his days in - although, considering that Gorath is interested in reformation of his whole people and not just himself and that Returning has burned all bridges to any future non-hostile contact with them, ever, that might be a Tear Jerker just by itself.