safari search google.com changed to google.be

If you want to fix your Google search to a specific Google location, I recommend that you download and install the free plug-in Glims:

http://www.machangout.com/

which not only does that but much more equally useful stuff!

(It adds items to Safari Preferences).

Not only does it already list a number of search engines and regions, but you can also add any other search engine not already listed in Glims by using the method described here:

http://www.machangout.com/tutorials/addsearchengine

Just enter the name you give the search engine in the name field, and the URL for it in the Query URL field.

As far as I know Google automatically uses your local search agent. Have you changed your timezone to Belgium or something? Or maybe you removed cookies from Safari?
Anyway, it is not necessary to use a third-party app to change to Google.com. Just go to the Google homepage and below the search field you will see (at the right) 'Google.com in English'. Click on it and you are on Google.com. You can save that as your default search agent at the top righthand corner in the Search Settings. And if you don't want Google to speak English you can change that in Search Settings as well (without returning to Google.be).