Don't be so sure!

MARTIN:Where are you going to spend your holidays this year, Gary?
GARY:We may go abroad. I'm not sure. My wife wants to go to Egypt. I'd like to go there, too. We can't make up our minds.
MARTIN:Will you travel by sea or by air?
GARY:We may travel by sea.
MARTIN:It's cheaper, isn't it?
GARY:It may be cheaper, but it takes a long time.
MARTIN:I'm sure you'll enjoy yourselves.
GARY:Don't be so sure. We might not go anywhere. My wife always worries too much. Who's going to look after the dog? Who's going to look after the house? Who's going to look after the garden? We have this problem every year. In the end, we stay at home and look after everything!