never in a thousand years
Not at any point; under absolutely no circumstances. never in a thousand years did I think that I would actually win the lottery! A: "Would you ever go on a date with Jake?" B: "Ew, never in a thousand years!"
not/never in a hundred, etc. ˈyears
(spoken) used to emphasize that you will/would never do something: I’d never have thought of that in a million years.