This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Deltora Quest
The spirit of Jasmine's mother appearing to Jasmine in The Forests of Silence, and Jasmine's reaction to it. Here's a girl's who hasn't cried for a long time, and she's reduced to tears at the sight of her dead mother's spirit. There's also the obvious grief she masks when she's telling the story of her parents' capture to Lief and Barda. In fact, the entire story Jasmine tells is one big tearjerker when you think about it. Lief's realisation that Jasmine probably has not cried for a very long time only adds to the emotion.
Jasmine's grief at having to send Kree back to the Forests in The Lake of Tears, when she, Lief and Barda are moving into Thaegan's territory. The two men see how upset Jasmine is at it, no matter how much she tries to hide it, and the mood is visibly dampened by it.
In Dread Mountain, Jasmine's sadness over not being able to dream of her father and see whether he is alive or not, and all because she cannot remember his face. Though she tries to act as if it's no big deal, you can see that her heart is breaking over it. And her words make it all the more tearjerking, as she chooses to think of her father as dead because she cannot bear to think of what he may have suffered in the Shadowlands. Come the end of the series, it's clear that her father did suffer a lot, and Jasmine was probably right when she said that it would just torment her if she knew.
Lief and Barda's grief over Jasmine's seemingly imminent death after she is hit by one of the Dread Gnomes' poisoned arrows. Also doubles as a heartwarming moment, as you can see just how much they have come to care about Jasmine since they first met her in the Forests of Silence.
Jasmine and Lief's grief over Barda dying from his gripper field wounds in Return to Del.
Towards the end of Return to Del, Doom regains his memory, realizing that Jasmine is his daughter. As he is partially unconscious, he starts crying and repeating conversations that he had with his dead wife, as Jasmine sobs beside him. Having two of the most stoic characters in the series break down is not an easy read.
I have something in both of my eyes...
It literally made this troper cry, and I don't cry while reading books as a rule. Especially when he begins conversing with his dead wife and Past!Jasmine and barely hears her when she tries to talk to him, and they are both crying, and I think I'll go bury my face in a towel.
The anime version is just as heartwrenching…
The look in Doom's eyes when he talks of Anna being dead is heartbreaking.
The moment when Lief's father sees Doom/ Jarred on the Place of Punishment. It never fails to bring tears, especially considering what happens soon afterwards.
The death of Lief's father Endon.
The death of Glock.
The revelation of what happened to the Aurons: They built a magic dome that kept out the monsters and resembled Pirra as it was, but it could only keep existing if those living within it believed that the illusion was truth and said nothing that contradicted it. The population eventually split into two groups, one who built rafts to live on and flourished, and the island-dwellers, whose number dwindled because kids were too impulsive and couldn't understand the necessity of lying. By the time Lief and co enter, there's one island-dweller left, and he's desperately trying to cling onto the past. And he dies horribly.
Jasmine's horror and grief at discovering that the sister she believed was trapped in the Shadowlands was actually a phantom designed to make her go to the Shadowlands and cause Lief to follow her there. The realisation that Faith cares nothing for her is truly heartbreaking, and also Jasmine's reaction to her revelation. Jasmine screams.
The death of Doran the Dragonlover. We spend two series learning more about this courageous posthumous character. And then it turns out he wasn't dead, but trapped in a particularly cruel form of And I Must Scream. Doran flat out says that death is far better than what can be called life. And he asks Veritas, one of his oldest friends, to kill him.
Verity's ultimate fate in Isle of the Dead. It's revealed that she was killed by Laughing Jack on the day of the Shadow Lord's invasion, during an impassioned fit of rage on Jack's part. She was only seventeen. She then spends the next eighteen years in a cursed half-state as a figurehead on board the Lady Luck.
Barda's reaction to seeing Lindal sick with the Toran Plague. He basically barges into Sharn's room with wild eyes, with Jasmine trying to hold him back. Then his breath catches when he sees Lindal unconscious on the bed and covered in welts.
Barda: Lindal! Is it true—?
Josef's death, and Lief, Doom and Ranesh's guilt over it.
The whole dialogue between Lief and Doom in Paff's room as they wait for Paff to wake up so that they can question her. What makes it all the more poignant is that Doom for the first time in all three series actually voices what's in his heart (and what he says is really heartbreaking). It's the first time we see him so undone. We hear that he actually empathizes with Paff, despite her being a Shadow Lord servant, because if he were in her shoes, he might have done what she did and he doesn't want her to wake up to utter despair like he did.
Paff's suicide. Even though she was a servant of the Shadow Lord, she is so broken and deep in despair that you have to feel sorry for her. Especially when you consider her history— a slave in the Shadowlands, being freed and returning to a home only to realise that she was completely alone, without family and friendless, and having to work for a fussy old man who constantly compared her to his old assistant. It's no wonder she turned to the Shadow Lord when you think of that. She worked so hard to please him and in the end he abandoned her, causing her complete loss of hope and will to live.
Lief being reprimanded by the spirits of Del's fallen. The spirit of Josef appears and only shakes its head as if saying there's nothing left for him to do.
Lief seeing Sharn dying in front of him from the 'Toran Plague'.
While he was still evil, the anime version of the former Jalis knight Gorl still managed to come across as a very tragic character.
In the episode "Meeting Prin", Prin is captured by Grey Guards and stuffed in a sack, who even plan to eat her. When she starts crying out to her mother for help they actually kick her to shut her up. While many consider Prin The Scrappy, this is still a horrible and cruel thing to do to an innocent child.
From the same episode, the elder Kin's story of what drove the Kin from their home in the mountains.
The anime had (believe it or not) Thaegan and her children, in the group's (minus Ichabod) final appearance. The part when Thaegan commits her Suicide Attack and her children didn't want to be left behind was sweet in itself. Then when she asks them why they did it, they tell her they just wanted to be with their mother. If that doesn't start the water works the fact that their deaths created a lovely rainbow will.
Speaking of Ichabod, his death scene is him refusing help from Lief before dying and joining the souls of his family.
Sorcerer Oacus's death was surprisingly tearjerking, considering he didn't even regret any of his actions. When he tells the heroes that the're fighting in vain, and that the Shadow Lord is too powerful to defeat he actually sounds slightly sad. Not to mention the part when he confesses that he was once a human, then he bursts into flames... talk about sad.
The fate of the sorceror Dann. He spent the rest of his life trapped in the Fell Zone in Weld's past, unable to return to Weld or see any of his friends or family again. And all because his best friend and advisor betrayed him by locking him out of the city.
Star of Deltora
Shadows of the Master
Britta's explanation of the fates of the Shadowlands survivors. They had been driven mad during their imprisonment, and even now suffer the effects of it. The fact that palace is now being used as a refuge for those damaged victims of the Shadow Lord's cruelty doubles as both a tearjerker and a heartwarming moment, as it's clear that the effects of the tyranny are being felt even twenty years after its end, and Lief cares enough about his people's well-being to try and help them recover from their pain and trauma and give them whatever they need.
Britta's grief and bitterness over her lost dream, and her longing at seeing the Star of Deltora.
Zoolah's death and Britta's reaction to it. She feels horrible, and it's worse for the reader since they know that the shadows that killed Zoolah were just trying to protect her. Also doubles as a heartwarming moment, as Britta actually feels some guilt at being associated with Zoolah's death, even after everything Zoolah had done and threatened to do to her.
The moments just before Britta and Stassi sink fully into the mud. Britta is grieved that she was unable to save the boy, and apologises to him. Then Stassi tells her that because she tried to rescue him, his life is now hers, and they just hold hands and wait for the mud to cover them.