Answered by Sayyidi Habib Umar bin Hafiz (may Allah protect him and benefit us by him).
What dhikr can a woman read to strengthen her resolve to wear the hijab?
Firstly she should remember that in wearing the hijab she is obeying the command of Allah. She should read the following ayah 70 times a day if possible, or at least ten times:
وَهُوَ اللَّهُ فِي السَّمَاوَاتِ وَفِي الأَرْضِ يَعْلَمُ سِرَّكُمْ وَجَهرَكُمْ وَيَعْلَمُ مَا تَكْسِبُونَ
Wa huwa-llahu fi’ssamawati wa fi’l-ardi ya`lamu sirrakum wa jahrakum wa ya`lamu ma taksibun
And He is Allah in the heavens and on the earth. He knows what you hide and what you reveal and He knows what deeds you perform. (Al-An`am, 6:3)