How do your proof yourself right despite having many negative reviews?

[Btaliat]

When a freelancer is in this mess, he doesn't need to be defensive. Rather he needs to make sure that he comes out with fact on order to get the clients convinced. Most of the times, it is always difficult for freelancers with negative reviews to get clients convinced but he can try by clarifying misunderstanding on the reviews. Therr is no need of using emotions to appeal to clients. Rather proof yourself right. What other things can be done?