What is the status of a Mahr (dowry) given by a groom to a bride when years later the bride, when asked, says she thought that was a gift and not Mahr?
All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
In principle what a bridegroom offers to the bride is a dowry unless there is evidence which proves otherwise, or that it is known form the customs that it is a gift and not a dowry. Muhammad Ibn Farmoozah [from the Hanafi scholars] said: 'If a man offers something to his wife and then they disagreed; she says that it was a gift and he says that it was a dowry. In this case it is his statement which should be taken into account provided he makes an oath to this effect if he has no other evidence, as he is the giver and he knows more to whom he gives, just like in the case he denies having donated something. It is as if he says: 'I leave this as a trust with you', while she denies and says: 'You gifted it to me'; as it appears that it is a dowry because it is an obligation to give the dowry whereas gifting is an act of charity, and it appears that he is trying to get rid of the obligation on him [dowry].'
It should be noted that a Fatwa which is based on a question is not enough for such matters on which people dispute, rather on should resort to authorities who deal with personal matters of Muslims, like Islamic centres and the like.
Allaah Knows best.
You can search for fatwa through many choices