Definition of you never know in US English:

you never know

phrase

informal
  • You can never be certain; it's impossible to predict.

    • ‘If the traders had to clear away their own rubbish, you never know, they may even make less mess during the day.’
    • ‘Of course, you never know, there might be an ambitious young politician who wants to run this campaign.’
    • ‘Maybe someone will smuggle me a contraband glass of wine, you never know.’
    • ‘And you never know, you might even find your game improves.’
    • ‘I know, at 42, some might consider me a bit long in the tooth by then, but you never know.’
    • ‘I like to think that I would have strength to do the right thing, but you never know, do you?’
    • ‘This is probably the best fun I am going to have all Christmas, but you never know.’
    • ‘Sunday's forecast is not good, and this is the worst way to end a series, but with three days left you never know.’
    • ‘Having said that I doubt very much whether that will be the case, but you never know.’
    • ‘So pick a name at random, and you never know, you might just hit on the right one.’