Ismailites, according to the view point of Muslim scholars, are not Muslims but a mixture of scattered groups with different beliefs. They deny the basic things in Islam which render them disbelievers. A Sunni Muslim cannot marry an Ismailite female.
In addition, the case of marriage between a Sunni and an Ismailite cannot be compared to the situation when marrying a woman from among the People of the Book (Jewish or Christian). Simply because the Qur’an stated that it is permissible for the Muslim man to marry a Jewish or Christian woman but not any body else. The reason that the majority of the scholars say that they, Ismailites, are a deviant group and cannot be concluded among the People of the Book because their principles and dogmas contradict the basic things in Islam. Accordingly, marrying an Ismailite follower is not allowed in Islam.