NAIVE

naïve [adjective] [esp. disapproving] - (too) willing to believe that someone is telling the truth, that people's intentions in general are good or that life is simple and fair. People are often naive because they are young and/or have not had much experience of life.Young, naive and trusting as I was, I believed every lying word he said.They make the naive assumption that because it's popular it must be good.We had a naive belief that with democracy and freedom would come prosperity.The plan exposed their naive idealism.It was naive of you to think Lawson would listen to your suggestions.