This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Sophistication and Betrayal
The protagonist being permanently stuck in Equestria, after having experienced a very painful and horrific Mind Rape for nothing.
Rarity breaking down in tears from the stress, after she gets tricked into opening on her day off and giving away a very costly discount.
Rarity's reaction to being stalked, and having her most intimate moments violated.
Cashmere finally breaking down and admitting just how heartbroken she was after Rarity declined her affections.
The finale combines both Tear Jerker and Manly Tears. While the story ends with Rarity and the protagonist finally getting married, he's immensely regretful and sad that his family can't be there with him, and leaves a pew at the front empty as a symbolic gesture of this.