Buffy was telling the Giles, Willow and Xander that she'd discovered Angel was a vampire.
"Are you alright, Buffy?" Giles asked, concerned.
"Yeah. I'm fine. He didn't hurt me."
"If he didn't hurt you, how did you find out he's a vampire? Don't you usually figure that out when they attack you?" Xander asked.
"No, we were kissing and then he changed."
"You couldn't tell while you were kissing him?" Xander asked, astonished. "I mean, they're room temperature and don't breathe. How'd you miss that?"
"I don't know, I just didn't notice."
"Aren't you supposed to be able to sense them? Could he be masking himself somehow? Giles, is it possible for a vampire to hide the fact that they're a vampire?"
"I suppose it may be possible. There are a variety of glamours that might make it possible."
"I don't know, guys. He just doesn't seem like a vampire. I mean he helped me with the Three. Maybe, he's a good guy." Buffy protested.
"Buffy, from what Giles has said, all vampires are demonically animated corpses, not Anne Rice tragic heros. If you can't tell he's a vampire, then maybe the reason he helped you is to put you off your guard. If he managed to hide the fact that he's a vampire, even for a little while, then there's something to worry about here." Xander said.
"Xander." Willow said frantically, trying to get him to shut up, certain he was making a fool of himself. "Your jealousy is showing."
"What jealousy?" He asked, confused. "Willow, I'm not feeling jealous. I'm worried. Everything we know about vampires, real vampires, says they can't be good guys. Which means he's up to something. He wants Buffy to think he's a good guy. He managed to hide the fact that he's a vampire for quite awhile. His control slipped and now you know. Either find out what the agenda is or stake him, or both. Giving a demonically animated corpse the benefit of the doubt seems like an invitation to death."
"Buffy, he may be right. I have never heard of a single instance in which a vampire, a real vampire, not one from a story, turned out to be good. They're soulless, they aren't able to be good. You should destroy him the first chance you have."
Later Buffy returned to library, still uncertain. "Did you find anything, Giles."
"Yes. In the Watchers diaries. I found mention of Angelus, he of the angelic face. Do you know if this Angel has a tattoo of a bird on his shoulder?"
"Yes. When he was hurt, I saw it. So Angel is Angelus."
"Yes, a particularly vicious vampires who earned himself a reputation as the Scourge of Europe. His preference was young girls. Buffy. I think you should consider Xander's idea that this Angel has an agenda. And remember, he's a vampire, not a person."
The next day after Buffy's mother has been attacked by a vampire and everyone thought it was Angel.
"You let him go?" Xander stared at her. "Why? He attacked your mother!"
"No, it wasn't him. It was another vampire, Darla. She attacked me and he dusted her to save me. He told me, he has his soul. He was cursed with it by gypsies. So he is a good guy."
"How do you figure that? First off, what proof has he offered that he has a soul? Can it be proven, Giles?" Xander asked.
"Yes, there are spells that can detect the presence of a soul."
"Then have him prove he has a soul. Beyond that, having a soul doesn't make someone a good guy. Souled people do some damn awful things every day, Buffy. Not to mention, can't curses be broken? Does he know what can break this curse, he says he has? Add to that, he hid the fact that he's a vampire. So where are you getting good guy out of this?"
"He helped me and saved my life, Xander!"
"So have I. So have have others. It doesn't prove anything. Without proof he's just another demonically animated corpse! Show me proof and maybe I'll accept the possibility that he's at least trying to be a good guy, but without proof, you'll never be able to convince me. Your belief is not enough."
"Buffy, I'm going to have to agree with Xander. Ask this Angel if he would be willing to let me examine him magically. Also, I would like details about this curse. It should be researched."
"Since when is my word not good enough?"
"This isn't about your word, Buffy. This is about people's safety. Taking chances with people lives based solely on one person's word has too much of a disaster potential." Xander told her. "If he really is a good guy and he really does have his soul, then he shouldn't have a problem with proving it. How will you feel if it turns out that this is a trick and people died?"
"That's a low blow, Xander." Willow protested.
"I don't think so. I think it's a necessary question. If you believe him, then why are you worried about what the tests might show? Or whether he'll agree to the tests?"
"I'm not worried, I just wish you'd trust me to know what I'm doing."
"It's not you I don't trust, Buffy. It's vampires. Until I see proof that a vampire actually has a soul and does good things, I will not believe it."
"Fine, I'll asked him. Happy now?"
"Not until we have proof. And we know what it takes to break that supposed curse. For all we know, it's you that can break it."