Prov. The truth will always be discovered. (Can be used to remark that someone who had been concealing the truth is now revealing it, as in the second example.) The embezzler may think that someone else will be blamed for his crime, but the truth will out. Ellen: Remember last week, when I told you I bought some shoes? Fred: Yes.... Ellen: Well, before you look at the bill from the shoe store, l ought to tell you that I bought ten pairs. Fred: Aha. The truth will out.
The facts will be known, as in She thought she could get away with it, but truth will out, and I'm sure she'll get caught . Shakespeare used this idiom in The Merchant of Venice (2:2): "But in the end truth will out." Also see murder will out.