I am engaged and I want to know if it is correct to go out alone with my fiance to public places like restaurants since these places are crowded and we never sit alone; we are always surrounded by people? Is it wrong to ride with him in his car during the day? If it is wrong, doesthis mean that hiring a taxi is also wrong since I ride with the taxi driver alone?

All perfect praise be to Allaah, The Lord of the Worlds.  I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

You should know that a fiancé is a completely alien (i.e., marriageable) man for his fiancée just as any other alien man is as long as the marriage contract has not been established. When both get married according to Sharee'ah, then he becomes her husband. Therefore, it is not permissible for a man to stay alone with an alien woman or to go out with her or to look after her. He may look at her at one time only, and that is when he is considering her for marriage.

It is not permitted for a woman to be alone with an alien man regardless of whether he is the driver of a car, a taxi or anything else. The Prophet said: “No woman should not be alone with an (alien) man unless she has a Mahram (i.e., unmarriageable person) with her, and no woman should travel except with a Mahram.” [Al-Bukhari and Muslim]

Also, Ibn 'Abbaas and his father, related that the Prophet said: “Whoever believes in Allaah and in the Last Day should not be alone with a woman without any Mahram. If he does, then Satan will be their third (companion).” [Ahmad]

Riding with an alien car driver is considered by Muslim scholars as the same as being alone with an alien man.

For more details please refer to Fatwa 81356.

Allaah Knows best.