Maintaining home with smart internal security within (9)

I believe the answer is:

insisting

I'm a little stuck... Click here to teach me more about this clue!

'internal security within' is the definition.
I can't judge whether this defines the answer.

'maintaining home with smart' is the wordplay.
'maintaining home' becomes 'sisting' (I am not sure about this - if you are sure you should believe this answer much more).
'with' is a charade indicator (letters next to each other).
'smart' becomes 'in' (as in fashionable).
'sisting' after 'in' is 'INSISTING'.

Can you help me to learn more?

I've seen this clue in the Sydney Morning Herald.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.