People across the globe believe that shia and sunni are the two different sects. Both of the sects have different religious beliefs, therefore it has been understood by people that they cannot come under the same umbrella ‘Islam’. Many people have this faith that due to the entirely different conduct of life, shia and sunni cannot marry with each other. However, before making such bold claims, complete research is very important to know the reality. So, before marrying with a shia man or woman, one must know that there are two types of shias:
One of the types of shia holds disbeliefs (kufr), that the Quran has been altered, Hazrat Ali (R.A) is worthy to worship and here Shirk (to worship someone other than Allah) occurs, the angel Jibril made an error in descending the revelation on the Messenger of Allah (P.B.U.H) in place of Hazrat Ali (R.A), accusations on Hazrat Aisha (R.A) of committing adultery or denying the Companionship Hazrat Abu Bakr (R.A).
However, the another type of shias are those who do not hold beliefs that constitute Kufr, such as believing that Hazrat Ali (R.A) was the rightful first Caliph after the demise of the Prophet Mohammad (P.B.U.H), belief in the twelve Imams, and all those beliefs which the first type of shias put faith in.
A true Muslim has asked by Prophet Mohammad (P.B.U.H) that before marrying, Muslim must need to check the religious beliefs, and religious practices in his/her partner. There is a Hadith in Sahih Bukhari that Messenger of Allah has said:
"A woman is married for four reasons, her wealth, lineage, status and Deen. Choose the one who is religious." (Sahih Bukhari)
Even then we being humans do not know that what faiths are hidden in the chest of people and what they are pretending, indeed! Allah knows the truth only. And so, we should avoid those things where we find doubts or dissatisfaction. If we go for things which are doubtful then we are tangling ourselves deliberately in the chaos.