If we don't accept you , what do you do
they usually ask this question to see how much you insist on getting this job so first of all you should show them that you really want this job and you are the most qualified person for this job
after that tell him that you wish not to be refused if happened you will going to improve yourself and try finding another opportunity in the same field
this is the idea of how to answer such a question hope you get it ,try to form your own answer ,share us with it after we get ur own answer we will share you a proper complete answer