Weird is always fun lol Well since Kira is secretly Satanic she knows all about faking emotions since she likes to try to read people like open books. Body language is something that gives away who's faking and who's not, plus who knows what sort of Truth spell she could come up with in order to see through Kore's innocence mask that she puts on for everyone. Kira wont notice immediately, but eventually she'll start observing and analizing out of curiosity