By Ryan Woo BEIJING (Reuters) – Chinese President Xi Jinping, in a recent reply to a letter from an Iowa native whom he first met nearly four decades ago, said the world’s future demanded stability in Sino-U.S. ties, according to Chinese state media on Wednesday. Bilateral ties have sagged in recent years, slammed by a trade war and a plethora of other issues, including the origins of COVID-19. Communications between the countries have improved since Xi’s talks with U.S. President Joe Biden in San Francisco in November, but both sides remain tense over democratically governed Taiwan, which Chi…