Sir / Madam,
I am confused in understanding this phrase. Kindly explain me with precise meaning using this phrase in a sentence form.
The phrase is actually: "You can't have your cake and eat it too."
The problem with eating a cake is that at the end of it, the cake is gone. You can either have a cake for ever, or you can eat it; but you can't do both.
This idiom means that sometimes you have to make a compromise, because you can't always have everything you want.