Tell her bluntly

"You're not dreaming. I was looking around the classrooms and found you here. The name's Matthew." you extend a hand to her with a smile. She smiles back and takes your hand.

"Well, then in that case, I have one question." She sits up slowly, her shirt falling onto her chest to reveal that she is sporting what might be an average pair of breasts. But your no pervert, so your eyes don't linger.

"Why was your face so close to mine? I know I ain't used to social graces, but... I don't think one wakes new people with a french kiss." she says with a grin.

"Uhhhhh..."