Yes; like usual, River has phrased Ned's exact thoughts, more simply and more poetically than he ever could. He comes back to the table and just sits there, stunned and smiling, cradling his tea between his hands. The warmth of the mug mirrors the warmth inside him, the vicarious joy of finding out that two of his friends are in love with one another.

"I can't believe it. I mean, I can, it's just-" he trails off, shaking his head.

A lot of the time, he's sure it's not all that nice for River. The way she is forced to see into everyone's heads. Ned is extrapolating based on his own experience, but he knows that his mind isn't all that pleasant a place to be, some of the time. Everyone else here is shielded from that. He can decide whether or not to let them get a glimpse of the fear, the doubt, the suspicion, the self-loathing, the disgust, the helplessness, and all the other bad things. With River, though, she must experience the unhappiness of everyone around her.

So it makes sense that she would be so moved by the 'fairy tale,' as she called it, of Charles and Erik being in love, or of the feelings that Ned is developing for Daneel. Their happiness is, in many ways, literally her happiness. Ned can enjoy it vicariously, but he also understands that it's more than that, for River.

"And they know that you know, of course?"