Is a wife required to explicitly ask her husband about his pronouncement of divorce, or is it more appropriate not to ask him, and what should she do if she is plagued by a nagging doubt about him having conditioned divorce upon a certain thing without certainty?

One must turn away from misgivings (waswas), stop being preoccupied with them, cease indulging in them, and refrain from asking about them. The wife is not obligated to ask her husband about the misgivings of divorce and the like that Satan casts into her heart, for divorce originates from the husband, and the decision regarding it is his.