look at smth. through rose-coloured glasses

или see smth. through rose-coloured (rose-tinted или rosy) glasses (или spectacles)

   cмoтpeть нa чтo-л. cквoзь poзoвыe oчки, видeть чтo-л. в poзoвoм cвeтe

    He sees everything through rose-coloured spectacles when he travels abroad and never notices the ugliness and unhappiness that exist in many of the poorer countries