I've always found writing emotional scenes for Chuck and a reader insert trickier than other pairings, honestly. The character's so armored by default—wealth, arrogance, that performative smirk. If the reader's emotional and he just crumbles immediately, it feels cheap. The tension comes from that armor cracking in ways he can't control. Maybe his voice gets quiet, not softer, but strained, like he's physically fighting to keep the usual drawl in place. Or he deflects with a cruel comment that lands flat because his hands are shaking.
I think the setting matters a lot too. A penthouse argument hits different from a quiet moment in the back of a town car. Use the trappings of his world against him. The perfect, cold marble of his kitchen island becomes a barrier; the expensive scotch he's nursing just emphasizes his isolation. The breakthrough shouldn't be a grand declaration, but something small and inconvenient—him catching the reader's wrist to stop them from leaving, not to pull them back, just to stop the movement, and his grip is too tight because he doesn't know his own strength. The emotion feels earned when he's fighting himself every step of the way.