How can some of the girl's family members be convinced to have the Islamic marriage contract (aqd shar'i) before consummation, and what is the ruling of Sharia on comparing the Islamic marriage contract to modern engagement?

The engagement (khitbah) is the man's expression of his desire to marry a woman, and her acceptance along with her guardian's. It is a promise of marriage, not a marriage itself. The rulings that apply to it include: the desirability of looking at the prospective fiancée, the prohibition of proposing to a woman already engaged to another, and the dislike of breaking off an engagement unless there is a legitimate Sharia (definition) interest. The modern engagement, which involves seclusion (khalwah), touching, and violating Islamic law, is impermissible.