(we don't know anything about her, and we have no proof that Spike does, either.)

Those are really good points: I hadn't thought about it that way before. If Xin Rong had family ties (which Spike didn't know about because he couldn't understand her dying words) and Nikki had family ties (which Spike also didn't know about because a) he didn't quite hear Robin's gasp while Spike was fighting Nikki and/or b) the writers hadn't thought of Robin yet), then why did Spike tell Buffy that it's her ties which make her different?

Was it just to mess with Buffy's head? (We know Spike was good at perceiving peoples' weaknesses and using them to manipulate.) Or did Spike really believe what he was saying, and if he did believe it, why did he?

Spike killed two Slayers -- if he'd killed more, he certainly would have bragged about it. We don't know whether he fought more than two. Still, if he'd fought others and escaped with his unlife yet failed to kill them, *and* come away with the theory that human ties hold a Slayer's death wish at bay, wouldn't that imply that Spike saw the other Slayers living with close ties, didn't see the same with Xin Rong or Nikki, and concluded those ties gave the other Slayers extra resilience?

It's a puzzle.

I love puzzles. *G*