I heard that Assia (Raziallhahu Talla Anhuma) "Wife Of Firoun" is going to marry in Jannah with our Prophet (P.B.U.H). Is it true? Please give me a reference of Hadith.

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, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

At-Tabarani reported from Ibn Mardawayh from Buraydah while interpreting the verse: {Previously married and virgins.}[Quran 66:5] that he said, "Allaah promised His Prophet Muhammad in this verse that he would marry him with a previously married woman (Aasiyah) the wife of Pharaoh and a virgin Maryam bint 'Imraan".

Ibn 'Asaakir reported from Ibn 'Umar that, "Jibreel (Gabriel) came to the Prophet and while with him, Khadeejah went past them. Jibreel told the Prophet to tell her that Allaah greets her and announce to her the good news that she will have a house in Paradise …and her house will be situated between the house of Maryam bint 'Imraan and Aasiyah bint Muzaahim". However, both narrations are very weak. Thus, what is reported in them cannot be used as evidence for anything.

We think that the issue of whether the Prophet will be married to Aasiyah, the wife of Pharaoh, or with Mary the mother of Prophet Jesus is not an important issue and discussing it is discussing an unknown matter which is unlawful. Thus, one should stop discussing matters that do not influence his religion or well-being.

Allaah Knows best.