u r right Dinesh ji.
The fleshy, juicy, attractive, fruit-like structure (known as 'cashew apple'; also edible when ripe) is actually the enlarged pedicel i.e. flower-stalk. Since it is not formed from ovary, botanically it is a pseudocarp i.e. 'false fruit'. Its job is to attract (a reward to) seed dispersors. Whereas, the 'real fruit' is the kidney-shaped hard shell (drupe) which contains the edible 'nut'.