The verb 'wish' is used to imagine/express a desire for things to be different from the way they really are.
We use the verb wish when we talk about something that is not likely to happen or something that is impossible.
Use ‘wish’ in situations, which are imagined, impossible or hypothetical.
• I wish I had more time. [Unfortunately, you know you don’t have anymore time to do something].
• I wish I could help you. [You want to help, but you know you can’t]
• I wish I hadn't spent all my money. [I need money now, but there is no money left, so it is impossible to do want I wanted to do.]
• I wish I were 25 years old again. [But I'm older than that, so it is impossible]
NOTE: There are other uses for the verb wish. I have provided the most often used usage of the verb.
I hope you understand my explanation. [There is a chance that you understand my explanation]