Followers of misguided sects should not marry Ahl al-Sunnah (Sunnis)
Question

Is it permissible for a young man from the Ibaadi madhhab to marry a girl who follows the Shaafa’i madhhab?.
Praise be to Allah.The Ibaadis are a Khaariji sect, which is one of the misguided sects. There are many saheeh texts which condemn them.
See the answer to question no. 11529.
In the answer to question no. 40147 we quoted the scholars of the Standing Committee as saying:
The Ibaadi sect is one of the misguided sects, because of their hatred, enmity and rebellion against ‘Uthmaan ibn ‘Affaan and ‘Ali (may Allah be pleased with them), and it is not permissible to pray behind them. End quote.
In Fataawa al-Shaykh Muhammad ibn Ibraaheem (13/30) it says that the testimony of an Ibaadi is not acceptable according to sharee’ah.
There are clear texts which describe how a woman’s guardians should make a good choice of husband for her. That includes ensuring that his religious commitment and character are acceptable. What kind of pleasing religious commitment can there be in those who follow misguided sects, who believe in rebelling against the rulers of the Muslims, who believe that the Qur’aan was created and that the one who commits a major sin is a kaafir, and who deny that we will see Allah in the Hereafter?
It was narrated that Abu Hurayrah (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings of Allah be upon him) said: “If there comes to you one with whose religious commitment and character you are pleased, then marry (your daughter or female relative under your care) to him, for if you do not, there will be fitnah in the land and much mischief.” Narrated by al-Tirmidhi, 1084; Ibn Maajah, 1967. Classed as hasan by Shaykh al-Albaani in al-Silsilah al-Saheehah, 1022.
Sunni women should not be given in marriage to followers of innovation, because the husband has a great deal of influence over his wife, and he may influence her to adopt his beliefs, so she moves from the saved group to one of the misguided sects.
And Allah knows best.