Summary:Why is it forbidden for a man and a woman who are not mahrams to have a relationship?
Islam forbids a man to be alone with a non-mahram woman (one who is not his wife or a close relative) even if he is teaching her the Qur’aan, which is the Book of Allaah That, is because the Shaytaan (Satan) would come between them.
Why is it forbidden for a man and a woman who are not mahrams to have a relationship?
Islam forbids a man to be alone with a non-mahram woman (one who is not his wife or a close relative) even if he is teaching her the Qur’aan, which is the Book of Allaah That, is because the Shaytaan (Satan) would come between them. Imam Ali (peace and blessings of Allaah be upon him) said:
لا يخلوا بامرأة رجل فما من رجل خلا بامرأة الّا كان الشيطان ثالثهما
“No man is alone with a woman but the Shaytaan will be the third one present.”{1}
If this woman wants to hear about Islam and read about it in detail, she can look at books about Islam that have been translated into different languages, so she can take the language that she understands, then if she understands what attracts her to Islam, she can become Muslim. If she does not understand something and wants someone to explain it to her, it is permissible (for her to speak to a man) so long as there is no khulwah (being alone with a member of the opposite sex) involved – so she could have a mahram (close relative) with her, or a group of women, and the man should be a trustworthy Muslim, or a group of trustworthy men who could sit with this woman and teach her about Islam so that she can understand it and proof be established for her. This is permitted.
Therefore, it is forbidden in Islam, and in the Qur’an it has been mentioned alongside such deadly sins as paganism, murder, and theft.
Footnote: Mustadrak Alvsayl, vol. 2, p. 553
Source:https://islamqa.info/en/9465