Answer: thatso

AnswerCrossword Clue
THATSO"Really?"
THATSO"Really, is ..?"
THATSOSkeptic's comment
THATSO"Oh yeah?"
THATSO"No kidding!"
THATSO"Oh, really?"
THATSO"Oh, yeah?"
THATSO"You don't say"
THATSO"Honest?"
THATSO"Oh really?"
THATSO"You don't say?!"
THATSODoubter's remark