(as) honest as the day is long American British old-fashioned
If you describe someone as honest as the day is long, you mean that she/he is very honest and reliable.
Jenny is as honest as the day is long in her response.
James is as honest as the day is long, he never cheats on an exam.
He wasn't as honest as the day is long with Mave, though.
To decide to believe someone‘s saying although they may not tell the truth
Used to say that what you're saying is true, or that you'll do what you promise .
trustworthy, stable, unlikely to fail
To be very serious
Used to allude that the last force, problem or burden which is seemingly minor and small causes a person, system or organisation to collapse or fail
Her husband's violent act last night was the straw that broke the donkey's back and she left him