Note popped in post, one with sympathy: a nice surprise? (11)
I believe the answer is:
serendipity
'a nice surprise?' is the definition.
(serendipity is good things happening unexpectedly)
'note popped in post one with sympathy' is the wordplay.
I cannot really understand how this works, but
'note' could be 're' (as in do-re-mi) and 're' is found within the answer.
'post' could be 'send' (synonyms) and 'send' is found within the leftover letters.
'one' could be 'i' (Roman numeral) and 'i' is found within the answer.
'sympathy' could be 'pity' (pity is a kind of sympathy) and 'pity' is found in the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for serendipity that I've seen before include "Fortunate chance" , "Fortunate happenstance" , "The accidental discovery of good fortune" , "Fortuitous happenstance" , "happy coincidence" .)