I am feeling really positive before those pith changes (1,4,3,3,4)

I believe the answer is:

i hope for the best

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'i am feeling really positive' is the definition.
I can't tell whether this defines the answer.

'before those pith changes' is the wordplay.
'changes' indicates anagramming the letters.
'before'+'those'+'pith'='beforethosepith'
'beforethosepith' with letters rearranged gives 'I HOPE FOR THE BEST'.

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I've seen this clue in the Sydney Morning Herald.

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