An online search is surface information . In legal practices there are hosts of conflicting rights which  do not exist in the public domain and do not eliminate the possibility that there exists conflicting rights. These information might obstruct the registration of your trademark. You can go ahead and file for your trademark without search reaching upto the registration stage.  However, registration stage does not guarantee acceptance . In situations of  opposition your application will be withdrawn from the process and  your brand will incur additional legal costs for mediation with the opposition.