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.
There are three criteria for identifying a disbeliever as a Muslim. They are:
1- By declaring the Two Testimonies of Faith, knowing that it is not necessary for non-Arabs to declare them in Arabic if this is difficult.
2- By being a Muslim’s offspring, like when the disbeliever’s child automatically becomes a Muslim when his father reverts to Islam.
3- By performing an act that is specifically related to Islam like, performing ablution, reciting the Quran or performing a complete Hajj. However, this does not include acts of worship that are common between religions like charity and fasting.
A non-Muslim is not to be considered as a Muslim or to be treated as such, based on a mere claim that he has adopted Islam.
Concerning the question of the bride uncovering her hair at her wedding, you may refer to Fatwa 90940.
Allaah Knows best.