remove bing redirect from safari

You have adware/malware installed. Use  Malwarebytes Anti-Malware for Mac. It may be necessary to run more than one scan. After scanning a couple of times, restart the computer and test. If necessary, follow the manual instructions.  Do not download any other programs that are listed in the articles.  

 https://www.2-spyware.com/remove-bing-redirect-virus.html

 How to get rid of Bing.com Redirect - Virus removal guide

Go to Safari Preferences/Extensions, uninstall any you don't recognize, and then turn all extensions off. Test. If okay, turn the extensions on one by one until you figure out what extension is causing the problem.

I happen to see a lot of these cases. And the typical solution is to remove the unknown configuration profiles. Just open your system preferences > see if there is a profile icon > tap it (if there is one) > remove unknown configuration profiles by selecting it and clicking the "-" button.