Wonderful place — no opening for larceny, reasonably secure (9)
I believe the answer is:
fairyland
'wonderful place' is the definition.
'opening for larceny reasonably secure' is the wordplay.
'opening' indicates taking the first letters.
'larceny reasonably' becomes 'airy' (I can't explain this - if you can you should believe this answer much more).
'secure' becomes 'land' (I've seen this in other clues).
The first letter of 'for' is 'f'.
'f'+'airy'+'land'='FAIRYLAND'
'no' is the link.
I am not very happy about this link. It may be part of another bit of the clue.
(Another definition for fairyland that I've seen is " fabulous state".)