A cat's persistent fear can be caused by a variety of reasons. When a cat first arrives in a new environment, it may feel scared and uncomfortable. In this case, you can provide the cat with a safe and comfortable space to allow it to gradually adapt to the new environment.

Cats may feel scared if they are in an unsafe environment or lack companionship and love from their owners. Make sure your cat has a safe environment and gives it enough attention and affection.
Also, if a cat has been hurt or frightened in the past, it may develop a fear of certain things or situations. In this case, it is necessary to patiently build a trusting relationship with the cat and avoid causing it further harm.