How can the impact of distance between two fiancés be alleviated, when one is studying in one country and the other is working in another, making it difficult for them to be together in one place?

If what is meant is marriage, then it is a great blessing for which Allah should be thanked, especially since you are still studying. It is important for the spouses to strive to be reunited in one country, to fortify each other, and to ward off causes of temptation, while frequently supplicating for this to happen. It is advised to work on strengthening faith and avoiding the enticement of Satan.