Women often reply to offers from guys with this answer, giving the guy some hope but in the back of her mind she knows its never going to happen.
Usually, when the girl responds she pretends to think about it first and makes a "hmmm..." sound before kindly replying with "maybe tomorrow".
Girl - "Hmmm.... maybe tomorrow."
Guy - "Hey there, can I come with you to your yoga class?"
Girl - "Hmmm... maybe tomorrow."