doughnut

Fig. to bet something of value against something worth considerably less. I bet you dollars to doughnuts that she is on time. He bet me dollars to doughnuts that it would snow today.

if you say that something will happen, dollars to donuts, you mean you are sure it will happen Dollars to donuts the company is going to fold. I'll bet you dollars to doughnuts she won't come to the party.

It's a virtual certainty, as in It's dollars to doughnuts that the team will make the playoffs. This metaphoric term pits dollars against doughnuts as in a bet. [Colloquial; late 1800s]

Stakes for a bet on a certain outcome. In the days when a dollar was worth more than it is now and a doughnut cost considerably less, someone who was reasonably sure that an event would happen might preface his comment with “Dollars to doughnuts . . .” as in “Dollars to doughnuts, it'll rain before nightfall.”