§ 117 — Estoppel

117. When one person (A) has by A’s declaration, act or omission intentionally caused or permitted another person (B) to believe a thing to be true and to act upon such belief, otherwise than but for that belief B would have acted, neither A or A’s representative in interest is to be allowed in any suit or proceeding between himself, herself or itself and B or B’s representative in interest to deny the truth of that thing.Illustration

A intentionally and falsely leads B to believe that certain land belongs to A and thereby induces B to buy and pay for it.

The land afterwards becomes the property of A and A seeks to set aside the sale on the ground that at the time of the sale A had no title.

A must not be allowed to prove A’s want of title.