Windowsill painting help

[kissmelittleass]

I have varnished windowsills in pine which I want to change, we're here when I moved in years ago and want to change.
Had decorators in 18 months ago and asked them to do it but they quoted a tremendous amount to do the windowsills and went into a long spiel about how hard it was to do!! Basically they just couldn't be bothered I think!
Any tips not sure how to go about it? Do I lightly sand, wipe down and paint white?
What paint should I use? No idea 🤷‍♀️

Some tips here but google internal wood paint.

harrisbrushes.com/how-to-guides/how-to-paint-a-window-sill/

My husband is a painter and decorator and his advice is to lightly sand, then prime with Zinseer 123 (red label) Then apply one coat of Dulux oil based undercoat and gloss or oil based satinwood.

I've painted varnished wood numerous times and agree with the pp, use a Zinsser primer and it's pretty easy.

Zinsser primer is what you need.

Thank you all for the tips I was clueless not looking forward to doing it but at least I know what to do now 👍