You won't believe this, but...

Meaning

Used to introduce an unbelievable or surprising story.

Examples

• John: <b>You won't believe this, but...</b> I saw a kangaroo hopping down Oxford Street this morning!
• Alice: No way! Seriously?
• John: I'm not kidding! <b>You won't believe this, but...</b> it even hopped into a bus stop.
• Alice: That's incredible! I've got to hear the rest of this story.