What are the causes of intense fear and anxiety concerning death and the loss of one's husband? And what is the way to rely upon Allah and rid oneself of these thoughts? And do estrangement and loneliness play a role in this?

Allah has placed contentment, joy, and delight in His obedience and the fulfillment of His commands. Faith and the abandonment of polytheism and sins lead to complete security and perfect guidance, whereas faith accompanied by sins leads to the foundation of security and guidance, but without their perfection. Hearts find tranquility in the remembrance of Allah, but remembrance by the tongue alone is not enough; it must be coupled with righteous deeds. If a servant adheres to the command of his Lord and is afflicted with some distress or anxiety, he should bear it with patience, for Allah, by His grace and mercy, makes that an expiation for his sins. The Muslim should renew his repentance and return to Allah, and if the state of distress and anxiety persists, it is advisable to present the matter to Muslim psychiatrists, as there might be an organic cause.