It means naive and easily taken advantage of. A person like that would have been called "a sap".

I agree with Neal and Jura. Only as an addition. If SOMETHING is sappy,it is extremely emotional in a rather embarrassing way. Ex: "It is a sappy film - take some tissues when you go to see it". Oh..Didn't see details.A wrong posting.Sorry.

Hi safaa unsophisticated, not worldly wise, green, (like the sapling of a tree), wet behind the ears, gullible, easily led.