Polite request to make someone happy (6)
I believe the answer is:
please
'polite request' is the definition.
(I've seen this before)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for please that I've seen before include "Asleep (anag)" , "Delight, satisfy" , "Cause (someone) to feel satisfied" , "Like" , "cheer up" .)