Hello Archisman Bhattacharya

Even if you select Bengali medium as the language for your NEET exam, the questions will be also given in English so that you can refer from English and Bengali if you do not understand any question in any one of the language, or even a part of it. Also your choice of the language in the exam paper will not affect your NEET score and rank in the merit list so you do not get the scope to compete for 100% MBBS seat.

Hope it helps you.

Your choice of language in NEET has got little do with securing a MBBS seat. Your marks and your Category play a major role in your rank in the merit list. Now the reason you are allowed to have the  NEET question paper in a local language is to help you understand the question paper easily given the fact that it has been your native language and it helps you understand the question easily. But this has  no part in securing a MBBS seat at all.