Promises breakfast food around the end of March (5)
I believe the answer is:
oaths
'promises breakfast' is the definition.
'oaths' can be an answer for 'promises' (I've seen this before). I'm not certain of the 'breakfast' bit.
'food around the end of march' is the wordplay.
'food' becomes 'oats' (I've seen this before).
'around' indicates putting letters inside.
'the end of' says to take the final letters.
The final letter of 'march' is 'h'.
'oats' placed around 'h' is 'OATHS'.
Can you help me to learn more?
(Other definitions for oaths that I've seen before include "four-letter words" , "truths may be established by them" , "Expletives" , "Profane expressions" , "Solemn promises or curses" .)