Just. The tung oil scene. Let me just sit with that for a moment.
"If anyone had a fragile spirit, it was she—an unknown soul from somewhere else." Jiang Xingzhou doesn't know she's a transmigrator, obviously, but he somehow understands that she doesn't belong here in a way that goes deeper than he can articulate. So he does this small, superstitious thing—puts a drop of tung oil between her eyebrows to ward off evil. And in that gesture, you can see everything about how he loves her: possessive, protective, but also genuinely tender in his own flawed way.
The carriage scene right after is where it gets complicated though. He's hungry for her, physically, and she's still angry with him about... well, everything. The manipulation, the deception, the fact that he tricked her into that first intimate moment. She says no, and he doesn't force it. He says "Later tonight then? I will be very gentle." And she says yes, but with that mischievous glint in her eye—she's plotting something. She's not a passive character in this relationship, even when she's being physically overpowered.
What really gets me is the line: "Just as she knew he would never marry her, she also knew that he loved her." This is the central tragedy of their relationship. He loves her in the only way he knows how—through control, through possession, through condescending protection. And she accepts it because it's the most love she's going to get, even though she knows it will never be enough. She knows his respect will always be reserved for a proper wife. She knows she doesn't belong in his world. And yet here they are, cooking egg-fried rice together at a remote relay station like some ordinary couple.
The moment he catches her cooking and says "Dear cousin, what fine dish have you made?"—that casual intimacy, that gentle smile—after everything we've seen between them, it's almost devastating. He's playing along with this domestic fantasy, and she lets him, even as she knows it can't last.