Reinforce means to make something stronger or better.
Enhance means to make something better. An example is if you were to go on a date, you would enhance yourself to look good for the other person.
Promote means to improve or make better too. Promote is a word commonly used in employment when you move up to a better position.
These words are generally very similar but are used in different context. When speaking, you would never say that you just got reinforced in your job.