I have a number of scenes in my story that involve two or more characters talking to each other about various issues, many of which wander into semi-philosophical discussion regarding some of the general themes of the story (e.g., the arguments you see between characters over life philosophies in manga/anime, some of the discussion of geopolitics in Game of Thrones, etc.) that also influence character development and relationships.
I have an outline for the story so I know the general gist of what is said and what happens in broad strokes. E.g., in one scene I know that one character says something that makes another upset and storm off, which is necessary to set things up for the next scene where I need the character to be alone and angry in order for something plot-important to happen. I know what the character's mindset is going into the situation, I know the very, very general idea of what is said, and I know how the character's mindset changes as a result of the conversation.
However, I am having a problem where I don't know what the character are specifically going to say to produce that result, or the arguments they are going to make. I have been working on this story idea for a decade now, and I remember what happened is I had some vague ideas about what specifically was said when I outlined the plot a decade ago, but since then I've forgotten what I intended to say (I've had issues with forgetting the dialogue of scenes while I was trying to write enough notes down in the moment to not forget them). It's the equivalent of knowing a scene summary but not the actual dialogue or points made.
So now I have this issue in that I don't know how to get my characters to make the point they are trying to make in this scene. They have very distinct voices, but for some reason getting them to actually say it coherently is hard (specifically because these are scenes that establish who they are as characters).
I'll use two scenes as examples, mostly because they involve the same characters (the male and female romantic leads of the story) and relate to the same issue.
- The first is the initial "meet cute" between the two romantic leads. The guy is distraught over a tragic, traumatic event in his life (which I do know exactly what it is but am not detailing here for copyright reasons), whereas the girl sees a stranger being upset and talks to him, talking him through the crisis and convincing him to pick himself back up. This is supposed to be one of the key moments in the story to show the reader they have chemistry and an emotional connection. However due to the plot (a star-crossed lovers story), the two of them have this meeting without either ever realizing who the other is (and that the girl just helped someone who is technically her greatest enemy), which is part of the dramatic irony of the scene.
- The second is a later scene between the two after their affiliations are revealed. The two are alone talking about something, the guy specifically feeling alone and unwanted, and the girl accidentally lets it slip that she feels the same way. This is the point at which the characters go from merely being interested in the other to actually having romantic feelings, and the point at which is becomes very apparent the two understand each other emotionally on some level. This leads into the characters gaining the motivation to take the actions necessary in the next scene.
As can be seen, I have an idea of what happens in these scenes and how it influences character development, but I cannot easily articulate what the characters say or the specific arguments they make. I know how they see the world and how the conversations affect their character development. This is a big problem because in some cases, like the above, these are really important scenes used to establish chemistry between characters, and without it their relationship feels plot-mandated rather than developing naturally. This isn't only the case with romantic scenes, but it's where the lack thereof is felt most strongly.
The closest I have been able to get is when I randomly have flashes of "oh, that would be an interesting point to make" and write it down, but ultimately that results in a rather incoherent argument that doesn't seem to have a point, and even worse does not build the emotional chemistry I am trying to create.
Given this, what does one do when they know the general gist of how a scene or a philosophical argument is supposed to go but cannot easily articulate what the characters precisely say?