im looking where one of the character is incredibly gullible because he/she hasn't been exposed to the world much or being childish or stupid
must have romance and no yuri please

if you aren't looking for shoujo there is angel densetsu.the romance comes up after the first few chapters....havent't read it much further so I can't tell you how it works out

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II HITO - it is not some cliché and I really like the main character

Chiruha from Dear is exactly like that. There is romance of course and plot is very interesting.