This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Ai Yori Aoshi
There are many moments in Ai Yori Aoshi that are TearJerkers, mainly of the Happy Tears kind. The chapter with Aoi-Santa-san giving Kaoru a dream of being with his mother ... Ocular Gushers here.
Kaoru finally introducing Aoi as his beloved fiance to all their friends.
The episode Moonlight. Tina lets everything out to a sleeping Kaoru, since she's leaving tomorrow, and couldn't bear to tell him it's supposed to be for good. She kisses him partway through. He then turns over and mutters Aoi's name. Tina now knows where Kaoru's love lies, though they've been hiding it out of necessity the whole time. Her expression says it all. * sniff* The fact that she's still shown to love them both dearly despite this is Tina's Crowning Moment of Awesome. Still choked up. The manga issues that "follow" the anime just raise the respect meter more.