Dealing with a wife who takes off Hijab after observing it

Q: I have a problem that I would like to consult you about. Around a year ago, I married a woman who did not wear the Shar‘y (Islamically prescribed) clothing. She used to wear short dresses, show her hair, and she did not cover her face, but I hoped that she would change after marriage, and we agreed upon this. By Allah’s Grace, we were married and I brought her to live with me in Riyadh. Allah has opened her heart and she has begun to wear long clothes and ‘Aba‘ah (a loose outer garment), and she started to cover her hair. However, the problem is that after a while, she began to rebel against these clothes and hate them, but she has continued to wear them, albeit unwillingly, apparently to please me. The problem now is that she does not want to cover her face and she still wears make-up when she goes out of the house. As a result, many problems have occurred between us because of this. She claims that the Din (religion) of Islam does not ask women to cover their faces. (Part No. 17; Page No. 184) On the other hand, she says that because she used to wear short clothes and not cover her hair, it will take time for her to change herself and get used to wearing Shar‘y clothing. I have spent a year trying to discuss this with her and persuade her, but she is still not convinced yet. We have had many long discussions, with me trying to persuade her, but to no avail. Her latest argument is that she alone will bear the sin for this, and when I told her that I am responsible for her before Allah, she answered that every person is responsible for themselves, and that I will not carry her sins. It has become very hard to convince her, and that is why I am writing to Your Eminence, asking for your help, and may Allah keep you safe. Would you please give me a written reply, so she can read for herself the ruling on this matter according to the Shari‘ah and the Din from the scholars, as she is not convinced by my words. I also have another question: How should I treat her if she insists on her position and continues to dress up when she goes out and does not cover her face? What is the Shari‘ah’s ruling on this obstinacy and stubbornness? I fear Allah and do my best to abide by the Qur’an and Sunnah (whatever is reported from the Prophet), but I am afraid that after we return to Egypt, she might revert to wearing short clothing once again. I have spared no effort in advising her by all possible means, such as books, tapes of good scholars on this matter, interviews from the radio and TV programs in this regard, and despite all that, I have failed to convince this lady. (Part No. 17; Page No. 185) What should I do with her? Please answer me and may Allah benefit you and keep you safe, and benefit Islam and Muslims through you.