She became Muslim but did not announce her Islam, and they want to arrange her marriage to a Christian
Question

                I have a Christian friend, but by the grace of Allah she uttered the Shahaadatayn and she has been praying and fasting for a few years, but without her family’s knowledge (specifically her mother). The problem is that the girl’s father was originally Muslim, but he left his family and became Christian in secret and married a Christian lady with a civil marriage, and they had daughters and sons. Their father and mother changed the name of the grandfather and the family name in the children’s birth certificates so that the name would be a Christian one, because the father's real name sounds Islamic. When the daughter grew up and found out the truth, and realised that she was Muslim by origin and by full conviction, she uttered the Shahaadatayn and started to pray and fast Ramadan and read Qur’aan. She wants to announce her Islam in al-Azhar ash-Shareef and marry a Muslim man, but her mother does not want that and has threatened to cut her off and she says that she is ill and that this may need to her death, and her daughter will be held responsible for that. She says that she is originally Christian and her birth certificate indicates that. With regard to her father, a while back he started to pray and he says that he regrets what he did in the past, but he cannot help his daughter to announce her Islam openly lest he be exposed to scandal, according to what he says. The mother of the girl wants to arrange a marriage to a Christian man so as to bar her way to Islam. She said to her daughter: If you become Muslim, I will cut you off for life and you will be thrown out of my house. What should the daughter do so that she can save her religious commitment and be safe from her mother’s harm or cutting her off? Will the daughter be sinning if she marries that Christian man under pressure from her mother, so that she will not be guilty of causing her death, for example, because of stress? I have told you this situation, as this friend asked me to tell you, because she wants to attain success in the Hereafter and is fully convinced of Islam, and she does not want to die as a Christian. She wants to find out the Islamic view on her situation and what she has to do in order to please Allah and His Messenger.
Praise be to Allah.
    Firstly: 

    We praise Allah, may He be exalted, for having guided our 
    dear sister to Islam and enabled her to pray and fast. We ask Allah to bless 
    her with steadfastness and strength and to guide her family and relatives. 

    Secondly: 

    It is not permissible for a Muslim woman to marry a Christian 
    man, and this is not regarded as a marriage; rather it is zina (fornication 
    or adultery) and immoral conduct. She has to refuse to do that by all 
    possible means, and hasten to announce her Islam in her official documents. 
    She can seek help in doing that from experts such as lawyers and the like. 
    If announcing her Islam will result in her mother cutting her off, or 
    becoming ill, or even dying, there is no sin on her for that, because she 
    will have done what is required of her, and obeying Allah and pleasing Him 
    takes precedence over obedience to anyone else. The matter is very serious; 
    it is the matter of kufr (disbelief) or eemaan (faith), so 
    there is no room in this case for emotion. Perhaps by declaring her Islam, 
    that will pave the way for her father and mother to become Muslim, even if 
    that is after a while. The point is that her remaining steadfast in Islam is 
    what is obligatory and essential. There is nothing beyond that except 
    apostasy and loss. It is not permissible for her under any circumstances to 
    marry a Christian man. She has to hasten to confirm her Islam according to 
    regular official procedures, then she should be gentle in announcing that to 
    her family, and she should seek the help of people who are experienced and 
    skilled in dealing with such matters. If announcing her Islam results in her 
    family cutting her off or becoming ill, she is not responsible for any of 
    that. 

    We think that the general circumstances now will be more 
    helpful in dealing with this matter than was the case previously. We ask 
    Allah to give her the joy of seeing her family being guided to Islam. 

    We should point out that the correct thing to say would be “I 
    have a friend who was Christian”, because now she is a Muslim. The 
    fact that she has delayed announcing her Islam does not mean that she has 
    not become Muslim. The one who utters the Shahaadatayn in a serious manner 
    has entered Islam, and is required to pray and do all other obligatory 
    deeds, and she has done that, praise be to Allah. 

    And Allah knows best.