Simplify the following text for a Grade 12 native English-speaking person.
Original: The relationship between Zanzibar government and Tanzanian Mainland has not been so well in recent years since Tanzania Prime Minister Mizengo Pinda 's remark about the Isles ' sovereignty that Zanzibar is not an independent country outside the Union Government , within which it can only exercise its sovereignty .
Simplified: The relationship between Zanzibar government and Tanzanian Mainland has not been good in recent years since Tanzania Prime Minister Mizengo Pinda 's remark about the Isles ' sovereignty . He said that Zanzibar is not an independent country outside the Union Government , within which it can only exercise its sovereignty .