The World Federation One Stop Fiqh

Ruling 2384

As long as the man and the woman are not confident (i.e. they do not have iṭmiʾnān) that their agent has said the formula, they cannot consider themselves legally married. Merely supposing (i.e. having ẓann) that the agent has said the formula does not suffice. In fact, if an agent says that he has said the formula but they do not have confidence in what he says, the obligatory precaution is that they must not heed what he says.