Shaykh Ibn Uthaimeen (rahimahullaah) was asked:

What is the ruling on muraasalah (correspondence) between young men and women,
knowing that this correspondence is free from immorality, ‘ishq
(passionate love), and I always begin the letters with وَجَعَلْنَاكُمْ
شُعُوبًا وَقَبَائِلَ لِتَعَارَفُوا (…and made you into nations and
tribes, that you may know one another.)[Al-Hujuraat 49:13]?

He, rahimahullah, replied:

“It is not permissible for anyone to have correspondence with a non-mahram woman, due to the fitnah (that is) involved. The one having the conversation may think there is no fitnah (in that), but however the Shaytaan remains with him until he seduces him with her and her with him.

The Prophet (salla Allaah ‘alaihi wasallam) ordered the one who hears of the Dajjaal to flee far away from him, and he said that a man may come to him as a believer but the Dajjaal will keep on at him until he
makes him fall into his fitnah.

Correspondence of young men with young women involves a great deal of
fitnah and danger, and it must be avoided, even if the questioner says that there is no love or desire involved.

As for men corresponding with men and women with women, then there is
nothing wrong in it except if it contains evil.”

Taken From The Book:

Fataawa al Mar’ah al Muslimah (2/578).

Shaykh Saalih al Fawzaan, may Allah preserve him, was asked:

What is the ruling on having conversations with young women by email and what is the ruling of it, if it is beneficial for example speaking to an woman poet (to benefit from her poetry)?

A:
The origin is that is not permissible if it is occurring from non mahram men for them (the women) due to what it contains of fitnah and harm, even if she is a poet because preventing harm has precedence over bring out good. Majority of the times the ending of (these cases) are awful due to the youth having conversations with young women (by email) …”

The reference is the official website of the Shaykh :

http://www.alfawzan.ws/AlFawzan/Fatw…57&PageID=1416

Translated by Abu Fajr Abdulfattah

The Ruling on Attending Training Sessions Which Have Free-Mixing Between Men and Women – Shaikh Ibn ul-‘Uthaymeen
Question: What is the ruling on attending training sessions which have free-mixing between men and women?
Answer: “If a necessity calls for that, then there is no harm, along with avoiding communicating with women and looking at them with desire”*.
[‘Ilaam ul-Musaafireen pg. 86]
* Translator’s Note:
With that being said, the Shaikh’s final view on the issue of attending free-mixing schools or areas is that it is prohibited. The following is the last fatwa the Shaikh gave on the issue, which was a few months before he passed away rahimahullah.
He was asked:
Question: What is the ruling on studying medicine in a free-mixing university. Is this considered a Legislated need?
Answer: “This is not a Legislated need. It is obligatory upon those responsible of the Islamic country to separate between the men and women because free-mixing is an issue. If the people stopped entering into studies, enrolling in universities, and what resembles that of free-mixing, it would force the ruler to distinguish and separate. I see that it is not allowed to have free-mixing in medicine and nor other than it.
Questioner: Even in the Legislated Sciences?
Answer: “Even in the Legislated Sciences except if the women gather in a [separate] place, which they enter from a [separate] door and exit from a [separate] door and there is no free-mixing with men”.
[Tape: Kalimah ila Du’aat al-Jazaair recorded 23 Safar 1421 found here: aloloom.net/vb/showthread.php?t=14870]
Translated by
Faisal Ibn Abdul Qaadir Ibn Hassan
Abu Sulaymaan