If you're attempting to use Safari on Windows you'll notice that the last version available is EOL and no longer supported. The following provides a resource for working around this issue.
You may consider using a service such as browser stack to test with. Using browser stack allows you to test your site with Safari on Windows without the need to put your own computer at risk by running outdated and insecure software.
Browserstack - List of Operating Systems and Browsers
Another option you have is to install WebKit on windows which might be sufficient for testing compatibility with Safari:
How to load the latest webkit on Windows
Ultimately, the use of Safari on Windows for normal use is a security risk and should be avoided and discouraged. These options should only be explored for testing compatibility with your website if you have users that cannot or will not update to a secure browser.
We have a resource about the fact that Safari is out of date and cannot load most sites via https: