Charming perhaps, knight splits cost (6)
I believe the answer is:
prince
'charming perhaps knight splits cost' is the definition.
I can't judge whether this defines the answer.
'perhaps knight splits cost' is the wordplay.
'perhaps knight' becomes 'n' (chess. I am not sure about the 'perhaps' bit.).
'splits' indicates putting letters inside.
'cost' becomes 'price' (synonyms).
'n' put within 'price' is 'PRINCE'.
Can you help me to learn more?
(Other definitions for prince that I've seen before include "Son of a royal house" , "King's son" , "Possible future titular head" , "Pincer movement around the royal" , "Royal personage" .)