Bet \Bet\, v. t. [imp. & p. p. Bet, Betted; p. pr. & vb. n. Betting.]

To stake or pledge upon the event of a contingent issue; to wager.

John a Gaunt loved him well, and betted much money on his head. --Shak.

I'll bet you two to one I'll make him do it. --O. W. Holmes.

Source: Webster's Revised Unabridged Dictionary (1913)