Maison Ikkoku/Tear Jerker

Maison Ikkoku starts off as a comedy, but it doesn't pull its punches when it resolves the various romantic plots. Spoiler Warning: these all happen at the end, starting with the ending of the second to last volume of the manga (in the Viz edition, English), and somewhere around episode 90 of the anime.
 * Through a combination of alcohol, miscommunication, and chivalry, Mitaka offers to marry Asuna even though he likes Kyoko better. Asuna sees a photo of young Mitaka smiling after he won second place at tennis, and asks him, "Is it my imagination, or is the smile in this photo ... the same smile you're wearing tonight?"
 * When Kozue talks to Godai she explains the difficult situation she's in since Godai proposed to her. He didn't -- it was a miscommunication. But Kyoko is within earshot, and she is emphatically unhappy. It is tough -- after being chased by two nice guys for a couple years, they suddenly both propose to other women, dooming her to a life of solitude.
 * After Godai finally proposes, Kyoko has one request: "Promise me... that even if it's by one day... you'll outlive me."