First of all, we would like to stress that during the time of engagement, the man and woman are not married and are not allowed to be alone with each other. It is forbidden for them to have intimate talk about sexual matters as they are not a husband and wife yet. The engaged couples should be moderate in their behavior and abide by Islamic morals in their speech.

Clarifying the Islamic ruling regarding the relationship between the engaged couples, we would like to cite the following fatwa issued by the eminent Muslim scholar, Sheikh Yusuf Al-Qaradawi, in which he states the following:
“Betrothal, literally, customarily and legally, is different from marriage. It is an introduction and a promise to marry. Books of language draw a difference between betrothal and marriage. Likewise, in custom there is a distinction between a fiancé and a married man. Similarly, in Islamic law (Shari`ah) there is a big difference between the two terms; so betrothal is no more than a declaration to marry a certain woman, but marriage is a complete relationship based on a sound contract and a solemn covenant that entails specific requirements, rights and consequences. The Glorious Qur’an refers to both betrothal and marriage in the course of its reference to the case of widows: “There is no sin for you in that which ye proclaim or hide in your minds concerning your troth with women. Allah knoweth that ye will remember them. But plight not your troth with women except by uttering a recognized form of words. And do not consummate the marriage until (the term) prescribed is run.” (Al-Baqarah: 235)
Betrothal, whatever the punctilious signs it may put on, constitutes no more than a promise of marriage. Betrothal, therefore, does not entitle a fiancé to any right other than keeping the fiancée for his sake, in such a way that no one else can propose to her. In a Hadith, it is stated: “It is unlawful for a man to make an offer of betrothal to a woman who is already betrothed to another man.”
the most important thing I would like to emphasize on in this regard is that a woman is considered to be foreign to her fiancé until they are married. She can be regarded as a wife only through a sound, legal marriage contract; the main pillar in the marriage contract is offer and acceptance, which has a well-known formula in custom and Shari`ah.
As long as the marriage contract has not been concluded, marriage, according to custom and Shari`ah, is not fulfilled, the fiancée is still regarded as foreign to her fiancé; so, he is not allowed to be alone with her nor to accompany her in any travel without the presence of any of her unmarriageable kin like her father or brother.
according to the law of Islam, whenever one wants to divorce one’s wife after concluding the contract of marriage and before consummation, one should give her half of the dower; Allah, the Almighty, says: “If ye divorce them before ye have touched them and ye have appointed unto them a portion, then (pay the) half of that which ye appointed, unless they (the women) agree to forgo it, or he agreeth to forgo it in whose hand is the marriage tie.” (Al-Baqarah: 237)
But if the fiancé deserts his fiancée, he will not be required to pay his fiancée any thing; of course he may only face some reproach or embarrassment, then how can a fiancée be given the same privileges as a married man before consummating marriage?”