swear up and down
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Related to swear up and down: swear blind
swear up and down
To make a very serious, solemn pledge, especially that one is telling the truth. Janet has sworn up and down that she wasn't the one to betray me, and I believe her.
Farlex Dictionary of Idioms. © 2022 Farlex, Inc, all rights reserved.
swear up and down
AMERICANIf someone swears up and down that something is true, they insist very strongly that they are telling you the truth. He swore up and down he was going to get the cash and bring it right back. I couldn't get it out of my head that maybe it was all part of his plan, although he swore up and down it wasn't. Note: The usual British expression is swear blind.
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012