What are the reasons for the estrangement of a sister in faith after a relationship of cooperation and love? Is it a trial, a consequence of sins, or an evil eye? And how should one deal with it?

It is not possible to determine with certainty the reason for what happened, but it is advised to be diligent in loving for the sake of Allah, as it is one of the highest ranks of faith. Those who love each other for the glory of Allah are considered among the people of high status. Among the reasons for the continuity of this love and good companionship are patience with harm, repelling evil with good, spreading greetings, giving gifts, and abstaining from coveting what others possess. Also, staying away from sins is important, as they can cause hatred and deprivation of sustenance. Cooperation among friends in learning is beneficial, and if one of those who love each other loves his companion more intensely, his reward will be greater.