It is quite likely that your film was reviewed when it was first released in the movie theaters. To locate reviews that may have appeared in newspapers and magazines, try using one of the library database.
In all EBSCO databases (Academic Search Premier, Communication & Mass Media Complete, and Film & Television Literature Index with Full Text) you can search for the title of your movie as general keyword and then select the document type limit Film Review.
Film & Television Literature Index with Full Text gives also access to Variety Movie Reviews. You can access the complete list of movie reviews by clicking on the top menu:
Nexis Uni can help you locate film reviews published in major world newspapers. You can select the News tab from the main dropdown menu, narrow down by Reviews as article, and then enter your search terms (i.e. the title of the movie that you want to review).
You can explore the Internet to find other film reviews. Some suggestions are available here: