Question Summary:
Can a sunni girl marry to a shiaa boy. They are not kaffar. He pray and have good iman. Can you pleas tel me more about shiaa.

Question Detail:

Can a sunni girl marry to a shiaa boy. They are not kaffar. He pray and have good iman. Can you pleas tel me more about shiaa.

Answer :

In the name of Allah, Most Gracious, Most Merciful
Assalaamu `alaykum waRahmatullahi Wabarakatuh
There are many different sects amongst the Shias.
Some sects (like the Tafdheelis) are considered as Muslims as they differ only on the issue of khilafa i.e. they deem Ali (R.A) more deserving to be a leader than Abu Bakr (R.A).
They also revere and honour all the Sahabah. (Khairul fatawa 1/374 Shirkat printing press, Kifaayatul mufti 1/289 Darul ishaat)
However the majority of present-day Shias (Ithna ashra/Jafaries/Imamiyyias) hold such beliefs which render them out of the fold of Islam.
The following beliefs of theirs are recorded in the works of their very own Ulama….
THE QURAAN HAS BEEN DISTORTED
(Note-We, unfortunately, do not have many Shia Kitaabs at our disposal. Therefore, we have quoted verbatim the exact texts of only those books which are at our disposal. As for those books which we do not possess, we have sufficed with the meanings alone. These quotes were mainly taken from Ahsan al fataawa, Khumaini aur ithna ashra and Irshad as Shia and other reliable kitabs. Some were also taken from the sites of reliable Ulama on the internet.)   
و من قول الامامية كلها قديما و حديثا ان القران مبدل زيد فيه ما ليس منه و نقص منه كثير وبدل كثير (الفصل 2-187(
((In every era all the Imamiyyas believed that the Quraan has been changed; added to it was not of it, much has been increased and decreased.))(Al-Fasl 2/187)
لو شرحت لك كل ما اسقط و حرف و بدل مما يجري هذا المجري لطال و ظهر ما تحظر التقية اظهاره من مناقب الأولياء ومثالب الأعداء!!!)الاحتجاج للطبرسي، ص 378،دار النعمان للطباعة والنشر – النجف(
((If I were to explain to you all that has been obliterated, distorted and changed, there will be much length, and such things will became apparent which taqiyyah  forbids to make apparent.))(Ihtijaj Tabary 378, Dar an     Numan, An Najf)     
ان الاصحاب قد اطبقوا علي صحة الاخبار المستفيضة بل المتواترة الدالة بصريحها علي وقوع التحريف في القران (فصل الخطاب 31 مخطوط(
((Verily all our companions agree on the authenticity of those ‘mustafeedh’ infact ‘mutwatir’ narrations which denotes emphatically on the interpolation of the Quraan))(Fasl al khitaab 31 Makhtut)
عن ابي عبد الله قال ان القران جاء به جبريل عليه السلام الي محمد صلي الله عليه و سلم 17000 أية (اصول كافي 671 طبع لكهنؤ(
((Abu Abdullah said: “Verily the original Quran which Jibraeel (A.S) brought to Muhammad (sallallahu alayhi wasallam) contained 17000 verses))(Usool al kafi 671, Lucknow)
The present Quran contains 6236 verses. Therefore the implication of the above mentioned statement is that two thirds of the original Quran is missing.   
ان القران لا يكون حجة الا بقيم(الكافي ج1  ص 169، دار الكتب الإسلامية، طهران(
((Verily the Quran cannot be a proof except with a ‘Qayyim’ Imam))(Al Kaafy 1/169, Dar al kutub al Islamiyyah, Tehran )
 
Their books suggest that there are more than two thousand (concocted shia) narrations which denotes upon distortion of the Quran.

..... < This is not the end of the Fatwa - Please visit http://www.al-inaam.com/fataawa/shia_kafir.htm to view the complete Fatwa >........

CONCLUSION
In light of all the above, it is apparent that the vast majority of present-day Shia’s are not Muslims. If the person in question ascribes to any of these heretic views, nikaah will NOT be permissible with him. (Imdadul Ahkaam 2/213 Maktabah Daul uloom Karachi, Khairul fatawa 1/374 Shirkat printing press, Kifaayatul Mufti 1/289 Darul ishaat, Bahishti zewar kitab an nikah)  In fact, the Shia kitabs show that it’s not permissible for Shias to marry sunnis, as they regard sunnis as disbelievers. “It is not permissible to marry a sunni because they are Kaafirs” (Tahdhidul Akaam, Manlaa Yahzurulul Faqih 3/258.)
If this person claims to be from the Tafdheelis (The group that are considered as Muslims), then too extreme precaution should be exercised. There is the possibility he will conceal his real beliefs and practice on taqiyyah. (Kifaayatul mufti 1/289-290 Darul ishaat)  Also keep in mind the Shia practice of mutah (temporary marriage).
 Bear in mind that even though it is permissible to marry the tafdheelis it is highly discouraged. (ibid) Marriage is a lifetime affair; therefore, you exercise extreme precaution. Whoever gives up something for the sake of Allaah, Allaah will compensate him with something better. We ask Allaah to make you strong and grant you a good life in this world and in the Hereafter.
And Allah knows best
Wassalam
Ml. Ismail Moosa,
Student Darul Iftaa
Checked and Approved by:
Mufti Ebrahim Desai
Darul Iftaa, Madrassah In'aamiyyah