What are the limits of permissible emotional speech between a suitor and his fiancée (who is not yet contractually bound to him), and is it permissible for them to go out together accompanied by a mahram for the fiancée?

The fiancée is considered a stranger to the suitor until the marriage contract is concluded. It is permissible for the suitor and his fiancée to speak to each other out of necessity, provided there is modesty and avoidance of flirtatious language. There is no harm in the couple going for a walk in the presence of a mahram (unmarriageable kin) of the fiancée, provided she adheres to the Islamic veil (hijab shar'i). It is preferable to postpone this until after the marriage contract to avoid the enticement of Satan. Both should understand that the other is a stranger to them, and they are only permitted what is permissible between strangers.