From Longman Dictionary of Contemporary Englishit’s difficult/hard to believe (that)it’s difficult/hard to believe (that)used when you are surprised that something is true Sometimes, it’s hard to believe we’ve been married for 50 years. → believe
Examples from the Corpus
it’s difficult/hard to believe (that)• It's hard to believe another child could do such a thing.• It's hard to believe, but we're fast approaching the dessert hour.• Female speaker It's hard to believe it's happened.• It's hard to believe just how dire it is.• It's hard to believe Marie's got a husband.• It's hard to believe now but I actually made do with hooks for a while!• It's hard to believe that he started painting in World War Two and is still painting today.• The ideological points are still there but it's hard to believe that totalitarian regimentation could be so tight. 