One girl's name for truth (6)
I believe the answer is:
verity
'for truth' is the definition.
(synonyms)
'one girl's name' is the wordplay.
I cannot quite understand how this works, but
'one' could be 'i' (Roman numeral) and 'i' is present in the answer.
'name' could be 'ty' and 'ty' is located in the answer.
The remaining letters 'ver' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for verity that I've seen before include "A lady" , "Truthfulness" , "Truth - girl's name" .)