Recognize their fear, but don't give into it. Know what their mission is. Two main forms of motivation 1. Intrinsic is better motivator. Example of going to work when hate job for extrinsic paycheck.
Real motivation is drive from within.
Example of students who did better till incentives were withdrawn. Help them build their own internal standards by your example. Develop their imagination. Help them to enjoy present. Teach them that happiness is a decision.