Unable to open safari

Do you have any updates in the App Store?

Do a backup, preferable 2 separate ones on 2 drives. Boot to the Recovery Volume (command - R on a restart). Run Disk Utility and select First Aid. Then re-install the OS.

Reinstall from macOS Recovery

OS X Recovery

OS X Recovery (2)

If the computer won't verify, go to /Library/Preferences/SystemConfiguration/NetworkInterfaces.plist. delete the file and restart.

Backup your Mac.

1. Try resetting permissions. Resolve issues caused by changing the permissions of items in your home folder - Apple Support

2. If this  doesn’t help, download EtreCheck: https://etrecheck.com/maspro  and post the report here.

      Click, “Free Download” button and then  “Click to download” button,

      open Downloads folder, click on it to open, and then select ”Open”.

      Click on the bouncing  EtreCheck icon in the Dock.

      “Choose a problem” from the popup menu box, and then “Start EtreCheck” in the dialog.

      Click “Share Report” button in the toolbar and select “Copy report” .

      Paste the report when you reply.

      Note: This is a diagnostic test. Reading the report will help us not make unnecessary suggestions.

    Download Safari Technology Preview and try as a test.

    Safari Technology Preview is a self standing developer version of Safari with some advanced features and latest bug fixes.

    Bookmarks will be automatically imported.

    After testing, you can remove it from Applications folder if you wish or continue using as default. 

Finder > Applications > Safari Technology Preview, right click and choose "Move to Trash".

    https://developer.apple.com/safari/technology-preview/