What is the difference between something desirable and something essential?

a: something essential is necessary
b: something desirable is not wanted

a: Something essential is something that is absolutely necessary, required, or crucial for a particular purpose or situation. It is something that is indispensable or fundamental.

b: Something desirable, on the other hand, is something that is wanted or preferred but may not be necessary for survival, functionality, or fulfillment. It is something that is attractive, pleasing, or appealing, but not essential.