Marriage with a shia

If a Shiʿa believes in the tahrīf (alteration) of the Qur’an, believes that ʿAlī (رضي الله عنه) is divine, believes that Jibrīl (عليه السلام) made a mistake in delivering revelation, denies the Companionship of Abū Bakr al-Ṣiddīq (رضي الله عنه), or falsely accuses ʿĀʾishah al-Ṣiddīqah (رضي الله عنها) of adultery, then such a person is outside the fold of Islam because these beliefs contradict matters that are definitively established as part of the religion. Consequently, marriage between such a person and a Muslim is not permissible, whether the Shiʿa person is a woman and the Muslim is a man or otherwise.

Likewise, if someone believes that the twelve Imams were appointed by Allah and that they possess infallibility (ʿiṣmah) in the manner claimed by certain Shiʿa sects, the specific details and theological implications of that belief should be examined carefully before applying a ruling of kufr to an individual. It is therefore better not to declare every person who identifies as Shiʿa a disbeliever merely on the basis of the label; rather, the person's actual beliefs must be established.

If an individual does hold a belief that constitutes kufr, then marriage to that person is not permissible. However, if the person sincerely repents from the kufr belief, abandons it without merely concealing it through taqiyyah, and expressly disavows those beliefs, then after genuine repentance and return to Islam, the ruling regarding marriage can be considered accordingly.

The quoted passage from Radd al-Muḥtār states:

 "وبهذا ظهر أن الرافضي إن كان ممن يعتقد الألوهية في علي أو أن جبريل غلط في الوحي أو كان ينكر صحبة أبي بكر الصديق أو يقذف عائشة الصديقة فهو كافر ؛ لمخالفة القواطع المعلومة من الدين بالضرورة".

(رد المحتار، 3/46)

“From this it becomes clear that if a Rāfiḍī is among those who believe in the divinity of ʿAlī, or believe that Jibrīl made a mistake regarding revelation, or deny the Companionship of Abū Bakr al-Ṣiddīq, or accuse ʿĀʾishah al-Ṣiddīqah [of adultery], then he is a disbeliever, because he contradicts matters that are decisively established as necessarily known aspects of the religion.”

And Allah knows best.