I've never gotten prompts for FE but oh my god I always thought there was such a gentleness to all of Marianne and Lorenz's interactions! Honestly Marianne has always been my babygirl and Lorenz's interactions with her are one of the things that really warmed me up to his character because it's one of those weird intersections where one character's weirdness over-formality actually gives another equally-weird character a space that they feel they can safely act in. :)
In the midst of a battle with Edelgard's forces, Lorenz is unhorsed and injured and Marianne injures herself in rushing over to his rescue. Lorenz, who is not only aware he has issues with getting along with the rest of the team but also knows Marianne still has issues with seeing herself as a burden or a curse despite being a vital healer, ends up chewing her out for risking herself in a moment of high emotion. He only catches himself when he sees she's tearing up, and attempts a fumbling apology. But just like that, the battle is over, and she hurries away from him, muffling her crying into her arm. Lorenz knows he fucked up, but there's also this internal tension of knowing that Marianne doesn't value herself, but then he's also confronted with the frustration of the noble instinct of things never being about him, but also being the noble self-sacrificing type being that much easier than really trying to engage with people on an equal and thus vulnerable level. He makes a point of tracking down Marianne, profusely apologizing, and, in a weird stroke of 'okay what's going to knock us out of this funk' offering to train via sparring. "Perhaps if we focus on each other on competitors, we can build our strengths instead of fearing our weaknesses! I vow to respect you in every regard as a sparring partner!"