Illustrations paragraph 9

If the wedding agreement was already made and one knows according to circumstances that the father-in-law will cheat the bridegroom regarding the dowry or support, it depends. If one knows that the bridegroom will only accept what one says to the extent of suspecting the father-in-law and ensuring he does not cheat him, or one knows that the bridegroom will not do anything without consulting a beis din, one may inform him if all the conditions are met. But if one sees that the bridegroom will annul the marriage agreement, one may not tell him for it is unlikely that all the conditions will be met.