You can check whether a trademark is already registered in the UAE through the Trademark Inquiry service of the Ministry of Economy & Tourism (moet.gov.ae).
After you log in to the eServices portal, you enter the proposed name or logo and its trademark class, then pay the inquiry fee. The Ministry sends back an official search report listing any identical or similar marks that are registered or pending.
For a broader preliminary check, you can also search the WIPO Global Brand Database. Because similarity assessments can be tricky, many businesses have a professional run the search before they file.