lay a wager

I will lay a wager, that your whole hospital has not had so much small-pox as Mrs. Katy Quincy.

From Familiar Letters of John Adams and His Wife Abigail Adams During the Revolution with a Memoir of Mrs. Adams by Abigail Adams

We resemble not the celebrated comedian, Mademoiselle Duclos, to whom somebody said: "I would lay a wager, mademoiselle, that you know not your credo!"

From A Philosophical Dictionary, Volume 10 (of 10) From "The Works of Voltaire - A Contemporary Version" by Fran?ois-Marie Arouet (AKA Voltaire)

I’ll lay a wager this is the spot where they live when they’re at home and go yowling about.”

From The Golden Magnet by George Manville Fenn

Then I'll lay a wager, Conti, that it is the portrait of the artist's own mistress.

From The Dramatic Works of G. E. Lessing Miss Sara Sampson, Philotas, Emilia Galotti, Nathan the Wise by Gotthold Ephraim Lessing

"Let us lay a wager on it," said the Englishman.

From Hans Andersen's Fairy Tales Second Series by H. C. (Hans Christian) Andersen