'Bright' and 'life' don't collocate. 'Bright' and 'future' do, though. It's common to say, for example, 'Our future looks bright' or 'There's a bright future ahead of us.' With life, we could use, 'good' or 'happy'.

I'm not quite sure what you wanted to say. You can say: We will have a better life. We will have a bright future.

This is Chinglish... We would say, "Our lives would be brighter"