(as) innocent as a lamb informal simile
Being faultless or guiltless
I didn't break your window. I swear, I'm innocent as a lamb!
I don't believe she did it. She’s as innocent as a lamb.
Being naive or inexperienced
I remember in the early days when I first joined the company, I was as innocent as a lamb.
They are trying to lure him down by compliments and flattery, but he doesn't realize it. He is as innocent as a lamb.
Be young or childish and not have had much experience
To lack experience.
Not inteligent, and unable to understand difficult and complicated things or ideas
If you fall for someone's trick the first time then they are at fault.
Are you going to mess with me again? Fool me once, shame on you; fool me twice, shame on me.