u/La_OccidentalOrient

The quickest example that comes to mind is Conquest's "I'm so lonely" monologue to Mark. If you've heard of the tv show the Blacklist, Reddington has a nice one "I'm a violent man" (you can find it on YouTube).

It's where one character confides something deeply personal about themselves to another character who they're about to kill (Whether if they succeed not withstanding). Usually happens between a main character and a side character so if one of them dies it doesn't matter.

Is there a trope for this? In fact, are there more examples?