nothing could be further from the truth
US /ˈnʌθɪŋ kʊd bi ˈfɜːrðər frəm ðə truθ/
UK /ˈnʌθɪŋ kʊd bi ˈfɜːrðər frəm ðə truθ/

1.
used to emphasize that something is definitely not true
:
•
Some people think I'm lazy, but nothing could be further from the truth.
•
He claimed he was innocent, but nothing could be further from the truth.