What words can be addressed to a believing young woman who has been afflicted by the death of her fiancé before their wedding, to strengthen her resolve and alleviate her sorrow?

It is recommended to be patient and seek reward from Allah during a calamity, for Allah Almighty gives glad tidings of prayer, mercy, and guidance to the patient. If Allah loves a people, He tests them to raise their ranks or expiate their sins. A believer must be content with Allah's decree, and whoever relieves a believer of a distress, Allah will relieve him of a distress on the Day of Resurrection.