Bonnie Bennett is not a spinster. That is simply Stefan Salvatore's opinion on the matter. But Stefan also happens to have had a great deal of alcohol at the moment, so it's hard to say whether or not that may be affecting his judgement.

(It's not. Bonnie is far too young to be a spinster.)

Regardless, Stefan is drunk and watching Buffy and Damon just as intently as Bonnie is (and possibly a certain army man who is very unhappy about the whole thing). He stares at them intently as he sidles up next to Bonnie, before glancing over to her with a frown.

"He didn't happen to confide in you that this is all part of some kind of hair-brained plan, did he?"