Visual cues: Contrasting color palettes (cool blues vs. warm reds). One character stands rigid; the other is bouncy. Story beats: The "accidental hand touch." The forced proximity scenario (stuck in an elevator/on a spaceship). The eventual softening of the angular character’s idle pose.
Modern 3D animation has expanded the range of romantic narratives, moving away from simple "prince and princess" tropes toward more nuanced explorations of love.
Focus on "accidental" touches—hand brushes, sharing an umbrella, or reaching for the same book. In 3D, you can animate these micro-interactions with high precision.
Create a specific "Blush" texture or mesh overlay that can be dialed up or down. A toon romance is often defined by the "Anime Blush."