A Part of China?

The mainland never will allow Taiwan's Separation.

Historically:

In 1291, Kublai Khan, Genghis Khan's grandson and founder of the Yuan Dynasty, set up a bureau and had jurisdiction over Taiwan, at that time Taiwan belonged to Fujian.

In 1885, Taiwan became a province of China

Since 1979, China adopted the policy of peaceful reunification and gradually evolved the scientific concept of "one country, two systems."

The "1992 Consensus", on the "one-China" principle and its respective verbal wording of both sides, was reached in a meeting in November 1992 held in Hong Kong by the Association for Relations Across Taiwan Straits of the mainland, headed by Wang Daohan, and the Straits Exchange Foundation of Taiwan, led by Koo Chen-fu.
The consensus is that "both sides of the Taiwan Straits adhere to the 'one-China' principle" and orally explain the principle respectively.

China will do its best to achieve peaceful reunification, but will not commit itself to rule out the use of force; -will actively promote people-to-people contact
-economic and cultural exchanges between the two sides of the Taiwan Straits
- start direct trade, postal, air and shipping services as soon as possible;

China plans on developing relations across the Taiwan Straits
-promoting the peaceful reunification of the two countries.
The Chinese mainland will protect the legitimate rights and interests of the Taiwan compatriots on the mainland in accordance with the law and continue to pursue the resumption of dialogue and negotiations between the two sides on the basis of the one-China principle.

In addition the China using the "one China" principle, the US also adheres to the principle -helps avoid conflict between the two countries