blauäugig sein
to be naive, starry-eyed or credulous
Origin
The image draws on the blue eyes of small children, which stand for innocence and guilelessness. In the figurative sense 'naive, credulous' the phrase became common above all in the 20th century.
Building blocks
Words in this expression
Examples
Es wäre blauäugig zu , dass sich das von löst.
It would be naive to believe the problem will sort itself out on its own.