The punishment for an unmarried person is a hundred lashes."Dating" as it is currently practiced in much of the world does not exist among Muslims.

(Muhammad) The Quran plainly and disgracefully commands men to beat their women as soon as they show any sign of disobedience to mans authority and orders.
It states in Chapter : As for these from women, fear rebellion, admonish them and banish them to beds apart and scourge them.
It is truly amazing that even for such loathsome behaviour, Islam orders leniency in punishment.
For example, only a married person who commits adultery is to be stoned to death.
The Prophet said: “…We proceeded until we came across a hole in the ground that resembled a baking pit, narrow at the top and wide at the bottom.
The first step in maintaining obedience is the warning.
The purpose of this beating is not to inflict pain but to bring the wife back to her senses and re-establish authority.
But do not beat your wife on the face or in such a way as to leave a mark on her body.
But this has all the ingredients that a classic romance novel does not...those candy-coated pages do not tell you about the heartbreak, the tears, the mood swings and the countless negative aspects that are the central to these relationships Everyday life becomes a misery..marks drop, daily moods start to depend on the current state of her relationship with the boy and many girls, totally misled by Shaitaan, even make dua for a �reconciliation.� In the worst possible scenario, which is frequently happening, the girl, in an effort to improve her �self image,� may turn to various other ways...smoking, clubbing, drinking and drugs..she may embark on a series of flings just to make herself feel �special� again.�The woman and man guilty of adultery of fornication, flog each of them with a hundred stripes: let not compassion move you in their case, in a matter prescribed by Allah, if ye believe in Allah and the Last Day: And let a party of the Believers witness their punishment.� As difficult as it might be to end such relationships, once we realize and acknowledge to ourselves that the novels to which we are exposed to from such an early age are totally based on a kuffaar way of life, which appears to be very appealing from the outside, but which bears no contentment, no real happiness, it will in sha Allah, be easy to do so.
We should realize, that while it is natural to be embarrassed to discuss such aspects of Islam with them, it is infinitely better for them, that we impart the correct knowledge of an Islamic way of life to them, than allow them to acquire the totally wrong concept of �love� from books, television, movies, and their friends and environment.
Its just soo haram and Allah punishes those who commit zina (sex before marriage and sex with another person besides your marriage partner)...