Right, I should probably explain my excessively weird format.

C to A are arranged like you would see in older Fire Emblem games, where the supports are quick conversations during lulls in battle. Or in the heat of battle, depending on your level of badassery. S level, on the other hand, is pulled straight from Awakening- A conversation which is had at the base between battles.

C :

*Show Hugh and Rosa, Rosa facing edge of screen*
Hugh: "Rosa!"
*Rosa turns*
Rosa: "Hugh?"
Hugh: "How're you holding up, partner?"
Rosa: "Really well! These enemies are pushovers!"
Hugh: "It's good to hear that you've as strong as ever!"
Hugh: "Hey... Listen. Rosa, I'm really glad that you came with me! I couldn't have made it this far without you."
Rosa: "Don't worry about it! That's what partners are for, right? You just keep searching- I've got your back!"
Hugh: "Thanks- But don't expect me to leave you to do all the fighting!"

B:

*Show Hugh and Rosa*
Rosa: "...Hugh?"
Hugh: "Ah, Rosa! Good to see you doing your best!"
Rosa: "Ah, same with you..."
Rosa: "Hey, Hugh. Do you remember back when we were kids?"
Hugh: "Yeah! You came over sometimes, right? I remember babysitting you and my sister- Those were the days- Peaceful. Back before They attacked."
Rosa: "Hey, the babysitting was my job! But... Yeah. I kind of miss those days."
Hugh: "I think we all do, Rosa. We just have to keep helping eachother out- Then we can all get through this nightmare. Together."
Rosa: "You're right... I just hope we don't lose anyone on the way."

A:

*Show Hugh and random enemy soldier*
Hugh: "I said, where is she?! My sister! WHERE IS MY SISTER, YOU DASTARD?!"
*Rosa slides in*
Rosa: "Hugh! What are you doing?! He's already dead!"
*Hugh backs up a little*
Hugh: "I..."
*Soldier vanishes, Hugh turns to face Rosa*
Hugh: "Rosa... I..."
*Rosa moves close to Hugh*
Rosa: "It's okay, Hugh. We'll get her back, I'm sure of it."
Rosa: "But... You have to relax sometimes. We're partners, right? That's what I'm here for- When you get tired, I'm here for you to lean on. Don't forget that."
Hugh: "But... Rosa... My sister..."
Rosa: "Yes, we'll find her! But you can't lose yourself on the way- We promised that we'd get out of this together, remember?!"
Hugh: "I..."
Hugh: "You're right, Rosa. I'm sorry. I got... Carried away."
Rosa: "It's okay, I know. Come on, why don't you take a little break- I'll keep you safe for a while."
Hugh: "Maybe... Just for a little bit."
Rosa: "Don't worry. Soon, we'll have your sister back, and you two can play together again! Right?"
Hugh: "Right. Okay, I'll keep myself safe for her... And you, too, Rosa. You're a true friend."

S :

*Show Hugh and Rosa, Rosa facing edge of screen*
Hugh: "...Rosa."
*Rosa turns*
Rosa: "Hugh!"
Hugh: "I-"
Hugh: "..."
Hugh: "Are you okay, Rosa?"
Rosa: "Of course I am! That's a silly question."
Hugh: "I guess so! Ha...ha..."
Hugh: "..."
Hugh: "Hey, Rosa? What are you going to do after this is all over?"
Rosa: "I'm going to play with you and your sister, obviously! Didn't we talk about this already?"
Hugh: "But... Rosa. You won't be able to play with us all the time. You're going to have to live somewhere, you know."
Rosa: "Can't I just live with you guys?"
Hugh: "No, Rosa... I mean for the rest of your life."
Rosa: "Yeah... With you guys, right?"
Hugh: "Rosa. I'm serious. One day you're going to grow up and get married. You'll have a family all your own. We won't be able to see eachother all the time, like this."
Rosa: "Oh, yeah? Well, I think that's silly! Why would I do something like that?!"
Hugh: "...Rosa. What I'm saying is that one day you're going to fall in love. You're a cute, strong, amazing girl... I'm sure whoever you set your eyes on will fall for you, too. But you just won't want to spend as much time with your friends, you know? There'll be someone more important for you..."
Rosa: "...You IDIOT!"
*Rosa moves close to Hugh*
Hugh: "Oww! Rosa, I-"
Rosa: "No. Shut. Up!"
Rosa: "You have no idea what you're talking about! How could you know anything about love?!"
Rosa: "You're a big idiot, who doesn't care about anything other than helping others- You never even try to think of yourself!"
Rosa: "How could you know anything about love when you don't even love yourself?!"
Hugh: "...Rosa...I..."
Rosa: "No! You've got me started, and I'm not going to stop until I'm done!"
Rosa: "You can't possibly know anything about love! Y-You... You can't even... Notice the feelings... Your own partner has for you..."
Rosa: *Sobs*
Hugh: "I- Rosa- You-"
Rosa: "Bwaaaaaaaaa!"
Hugh: "...Rosa."
Rosa: "W-What?!"
Hugh: "Get up. You're stronger than this!"
Hugh: "You're my partner, after all. The one who's going to watch my back the rest of my life, right? If you're going to dissolve like this... I don't think I'm going to live for very long."
Rosa: *Sniffle*
Rosa: "You... Mean it?"
Hugh: "Absolutely. Now, isn't there something we have to tell the others?"
Rosa: "Hugh... I'm glad you choose me to be your partner."
Hugh: "Me too, Rosa. Me too."