This does nothing for me, but is it what you want?

Public Function gs(sSearchstring As String, Optional sGooglesite = "de")
    Dim sGoogle, sGoogle1, sGoogle2, sURL As String
    'please replace "URL of google" with the URL of google, as I am
    'not allowd to post links
    sGoogle = "URL of google/search?hl=" & sGooglesite & "&q="
    sGoogle2 = "&btnG=Google-Suche&meta="
    sGoogle1 = Replace(sSearchstring, " ", "+")
    sURL = sGoogle & sGoogle1 & sGoogle2
    gs = sSearchstring
    Application.Caller.Hyperlinks.Add Anchor:=Application.Caller, Address:=sURL
End Function