This is the 14256th most frequent Russian word.
останавливает
"Stops" or "is stopping."
Here, 'останавливает' is used in a metaphorical sense to indicate that fear is not being a hindrance for him, essentially not holding him back.
Его не останавливает страх перед трудностями.
His fear of difficulties does not stop him.
Here, 'останавливает' is used in reference to a mechanical or automatic cessation of movement, attributing the action to an entity.
Машина внезапно останавливает своё движение посреди дороги.
The car suddenly stops its movement in the middle of the road.
In this context, 'останавливает' is used in a literal sense to indicate physically halting someone for a specific purpose or reason.