Hazrat Umar (R.A) related that the Prophet Muhammad (peace be upon him) said, “Not one of you should meet a woman alone unless she is accompanied by a relative (mahram).”
The Prophet also reportedly said, “Whenever a man is alone with a woman, Satan is the third among them.” When young people are getting to know each other, being alone together is a temptation toward wrongdoing.
At all times, Muslims should follow the commands of the Qur’an (24:30-31) to “lower their gaze and guard their modesty….”
Islam recognizes that we are human and are given to human weakness, so this rule provides safeguards for our own sake.