(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
To be very wet
Because of forgetting bringing an umbrella, I look like a drowned rat when it rains.