That which troubles true lady? (8)

I believe the answer is:

adultery

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'that which' is the definition.
I can't tell whether this definition defines the answer.

'troubles true lady?' is the wordplay.
'troubles' indicates anagramming the letters (I've seen 'trouble' mean this).
'true'+'lady'='truelady'
'truelady' is an anagram of 'ADULTERY'.

Can you help me to learn more?

(Other definitions for adultery that I've seen before include "form of betrayal" , "Extramarital affair" , "Unfaithfulness to one's spouse" , "excluding union involvement?" , "Betrayal of a partner" .)

I've seen this clue in The Sun.

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