What is the advice for a young man and woman intending to marry, who have performed Istikhara, and the girl received a message that this is the correct choice for them, while the young man did not see any sign, feeling, or dream? What should they do about this, and what is the required duration for Salatul-Istikhara, is it three or seven days?

The evidence for Salatul-Istikhara (the prayer for guidance) is what Al-Bukhari narrated from Jabir ibn Abdullah. As for the saying of some people, "Then he proceeds with what his heart feels at ease with," there is a very weak hadith concerning it. The correct view is that the facilitation of the matter by Allah after the supplication is a sign of its goodness, and the presence of obstacles is evidence that Allah has averted His servant from that action. This is clear from the Istikhara supplication itself. Some scholars have said that it is preferable to do what one intended afterwards, as whatever occurs after it is good. Among the widespread superstitions is linking Istikhara to dream visions, and there is no sound evidence for that. The feeling of ease in the heart should not be the only sign, but it can be one of the signs. Shaykh al-Islam Ibn Taymiyyah said: "If one seeks guidance from Allah, then whatever his heart feels at ease with and whatever matters are facilitated for him are what Allah has chosen for him." There is no specific duration for Salatul-Istikhara, and it is permissible to repeat it and to supplicate before or after the salutations (taslim).