you bet 当然；你可确信

这条俚语来自美国，是It would be safe for you to bet on it. 的省略语；但也有人说是You can bet your life. 的省略句。

例：

—Freda: I expect father knows captain Keith. 父亲大概认识基斯船长。

—Keith: You bet he does. 当然认识。

（J. Galsworthy: The Eldest Son, act I, scene 1）