Phrases Expressing Surprise or Shock

I'm utterly flabbergasted.

C2

Meaning

Extremely surprised and astonished.

Example sentences

John: 'We won the lottery!'<br>

Alice: 'I'm utterly flabbergasted! I can't believe it!'

John: 'I'm utterly flabbergasted. It looked so authentic.'

Alice: 'The painting was a forgery.'<br>