This is reality: being ruthless to make time (5)
I believe the answer is:
truth
'this is reality' is the definition.
(thesaurus)
'ruthless to make time' is the wordplay.
I cannot quite understand how this works, but
'time' could be 't' and 't' is present in the answer.
The remaining letters 'ruth' is a valid word which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
'being' is the link.
(Other definitions for truth that I've seen before include "known facts" , "Actuality" , "Veracity; established fact" , "Veracity, faithfulness" , "Verity" .)