Please don't list this on a work's page as a trope. Examples can go on the work's YMMV tab.
Tear Jerker: Tasogare Otome X Amnesia
Just... The fact that Yuuko's been wandering around the school, completely invisibility, or sometimes when seen at all, she's seen as a horrible monster for decades. It's no wonder she became so attached to Niiya so quickly. He's the only one she has.
Episode 10. All of episode 10 is either this or Nightmare Fuel. You get to see Yuuko before the human sacrifice, and she's one of the nicest people you could hope to meet. Andthen...
More so if you think about it from Teiichi's perspective. It's not been long since he confessed his feelings for Yuuko and then is powerless whilst watching the very answers they've been seeking playing out in front of him. He tries to stop her from effectively walking into a trap, but has no power to change Yuuko's memories. By the time she is selected as the Human Sacrifice, he looks emotionally drained and can only speak words of sympathy in response to Yuuko's pains, none of which will get through to her. Again, it doubles as Nightmare Fuel as he's watching the girl he loves suffering and dying.
If you think a little deeper about it, it gets even worse. He was there the whole time. The whole time, and could feel everything she felt. Remember, she didn't die of blood loss, nor was she Mercy Killed. It's pretty clear from her physical appearance(the dried and drawn back lips, the shaking, etc) that she was dying of starvation and thirst, and that he had to watch (and feel) the love of his life die that long, slow death, while dealing with a broken leg that has a a bone sticking out of it for days. Dying of starvation and thirst on its own is incredibly painful, dealing with a broken leg, with a bone sticking out of itat the same time... On top of that, you have what's mentioned above about not being able to do anything about it, or even give her any form of comfort as she lay there, dying, alone, literally finding out what she is in the dark, and almost giving in.
Last 1/4th of episode 12. Yuuko finally disappears. The music didn't help any.