Little Miss Muffet
Potential
I'm just wondering. If Buffy would of somehow for whatever reason turned evil would he be able to kill her?
What about Spike? Could he have killed her?
To save the world, Angel could.
Spike would let the world get sucked into hell before he let anyone, (least of all himself), lay a finger on Buffy. He's already said so.
PS: I think that sort of nicely sums up the difference between the two vampires regarding the way the love her of course, and the way they live life.