곧이곧대로 믿다 (go-chi-got-dae-ro mid-da) – take everything as it is/believing something (gullibly)
This phrase has a negative connotation and you don’t usually use this unless you’re referring to a kid or naive person.
Another way you can use it is to warn someone not to be naive.
그 잚은 소녀는 가족 배경이 간단해서 정말 순진하고 누구의 말도 곧이곧대로 믿을 거라서 걱정해.
That young girl’s family background is simple so she’s really innocent and will believe whatever anyone says so I’m worried for her.
그녀는 사기꾼인다고 들어서 그녀가 하는 말은 모든 곧이곧대로 믿지마.
I heard that woman is a con artist so don’t just believe everything that she says.