Ara-anna, I look forward to hearing your thoughts on the book.
(And if you can't see the show on stage . . . well, there are ways.
)
TM, it probably partially depends on the actor and what he decides his motivation is there (and your interpretation). Galinda said that he would be her hero if he took Nessarose to the dance, so maybe he wanted her to have a good time so Galinda would approve. Maybe he didn't know what else to day, or didn't want Nessarose to feel bad.
Cem, I don't think it's clear at all from the soundtrack. It sounds like he's nervous and flustered, but could well be because he IS attracted to her, not because he's lying.