Dictates one way to prove gold genuine (4,4)
I believe the answer is:
acid test
'prove gold genuine' is the definition.
I can't judge whether this definition defines the answer.
'dictates one way' is the wordplay.
'one way' indicates an anagram (another way of arranging the letters).
'dictates' with letters rearranged gives 'ACID TEST'.
'to' acts as a link.
Can you help me to learn more?
(Other definitions for acid test that I've seen before include "Severe trial; old assay method" , "Severe or conclusive examination" , "Conclusive trial of success or value" , "'Appraisal to show the true value (4,4)'" , "Rigorous or crucial appraisal" .)