Optimistic desire, 1/100? (4)

I believe the answer is:

hope

'optimistic desire' is the definition.
'hope' can be an answer for 'desire' (I've seen this before). I'm not certain of the 'optimistic' bit.

I cannot understand how the rest of the clue works.

(Other definitions for hope that I've seen before include "writer" , "'. . . . springs eternal in the human breast'" , "Confident expectation" , "Trustful expectation" , "Feeling of expectant desire" .)

I've seen this clue in The Guardian.

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