"Safari wants to use your confidential information stored in "website" in your keychain"
Open Keychain Access.app in your Utilities folder. Highlight one of
  familiar keychain entries on the right side or type a familiar name in
  the spotlight panel. 
  
  Then double click the entry. When the panel opens, select "Access
  Control".
  
  In the "Always allow access" panel, click on the +, then navigate to
  Safari in your Applications folder. Save changes.
  
  Just for good measure, go to the Keychains Menu>Keychain First-Aid and
  select "repair". If any errors appear, rerun until you get a clean
  pass.
  
  Close Keychain Access and restart Safari.


source:https://discussions.apple.com/thread/2060870?tstart=0