I don't believe it
An expression of surprise and/or incredulity, possibly bordering on vexation. I don't believe it—I have the winning lottery ticket! So you came crawling back to us after all. I don't believe it.
I don't believe it!
an expression of amazement and disbelief. Bob: Tom was just elected president of the trade association! Mary: I don't believe it! Bob: They're going to build a Disney World in Moscow. Sally: I don't believe it!
I don’t beˈlieve it!
(spoken) used to say that you are surprised or annoyed about something: I don’t believe it! What are you doing here?