It may be simple to engage one's attention (8)
I believe the answer is:
interest
'attention' is the definition.
(thesaurus)
'it may be simple to engage one's' is the wordplay.
I cannot quite understand how this works, but
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is located in the answer.
'be' could be 'rest' (resting is a kind of being) and 'rest' is present in the answer.
'one' could be 'i' (Roman numeral) and 'i' is present in the answer.
The remaining letters 'ne' 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 interest that I've seen before include "Pursuit" , "Money made by or paid for money" , "Proceeds" , "Money found in street" , "Cost of borrowing" .)