The Prophet's (peace be upon him) guidance on curing fear and insomnia is the best guidance in my opinion.
At-Tirmidhi narrated in his Sunan that Khalid once complained to the Prophet (peace be upon him) that he does not sleep well at night. Prophet (peace be upon him) said,
"When you go to bed say, 'O Allah! The Lord of the seven heavens and what is under them, the Lord of the earths and what they carry, and the Lord of the devils and whoever they misguide!
Be my supporter against the evil of all of Your creation, preventing any of them to cause me any harm or injustice.
Mighty indeed are those whom You support, honorable indeed is Your praise, and their is no deity worthy of worship except you.'"
Also, At-Tirmidhi narrated that the Messenger of Allah (peace be upon him) used to teach his companions these words when they face any fear,
"I seek refuge with Allah's perfect Words from His anger and torment, and from the evil of His slaves and the whisperings of the devils. I seek refuge with You, my Lord from their presence."
Ibn Umar (may Allah be pleased with him) used to teach these words to his children and would even write them for those who were not able to memorize them.
There is no doubt that such words are suitable and effective in removing and repelling all types of harm and good guidance on curing fear and insomnia.