Safe haven — at first, only what it seems (5)
I believe the answer is:
oasis
'safe haven' is the definition.
(I've seen this before)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for oasis that I've seen before include "Place of calm in troubled times" , "quiet spot" , "place of refuge" , "Peaceful area away from trouble" , "Area of calm amid hectic surroundings" .)