Islam is a religion which provides set of rules to guide us to the best path in belief, worship and life. In order religion to be fruitful in our life it must be practiced as a whole. Indeed, when we practice Islam we become more mature and perfect human beings. The foundation of worship and good manners is Islamic faith. Before practicing any religious obligation a person must posses a sound belief. Individuals should strengthen their faith daily, because, any weakness in faith reveals itself in our actions and manners. However, the strong faith cannot be possessed in a short time, rather, it requires long term struggling. The entire life is a maturation process which we try to improve ourselves through the guidance of religion. Islam aims to educate or maturate its followers gradually. God and His Messenger did not command all religious obligations at once, rather, Islamic education and gradual revelation were completed in 23 years. Even, the command for women to cover their head came several years after Hijra which means women were ordered to cover their head 20 years after the first revelation. This is a important lesson for all Muslims with regards to educate their children or new Muslims in religious instructions. Before offering any religious obligation they should know if the addressee is ready to carry out it. If they have some concerns the guides or teachers should not rush to offer those religious obligations for them to practice. Otherwise, the children or new Muslims may abandon religion all together. In short, it is very important to take into consideration psychological, social and cultural conditions before telling people to practice Islamic rulings.
After this introduction, I would say to the person who asked the place of hijab, covering head is obligatory in Islam as any other religious obligations. If a person does not practice the hijab she becomes sinner but still considered Muslim. As far as I understand from the questioner that she does not want to wear hijab. It is not proper to approach her with the mentality that she has to wear it. The best way to deal with her is emphasizing on the matters of faith and giving her time to internalize Islamic belief first and then practice. In this regard, the books which strengthen our faith can be advised to her. Additionally, she can talk with a scholar and take religious advise. But, the scholar should not be rigid minded who distant people from religion.
