China’s chief, Zhou Xiaochuan, is trying hard to dispel worries about China’s economic strategy. However, Asian central bank heads have a string tendency to say one thing and do another.

With that backdrop, please consider G-20 Hears China Say There Will Be No Yuan Devaluation.

China emerged from the weekend Group of 20 meeting with a new measure of trust from major trading partners that it won’t significantly devalue the yuan. Persuading investors might be tougher.

Chinese Premier Li Keqiang and central bank chief Zhou Xiaochuan worked hard to dispel worries among visiting G-20 finance ministers and central bankers that their economic strategy hinges on weakening the yuan’s exchange rate.

The message was “heard loud and clear” that Beijing has “no intent, no determination, no decision whatsoever to devalue the yuan,” said Christine Lagarde, the managing director of the International Monetary Fund, after the weekend meetings in Shanghai.

Global anxiety had grown in recent weeks that China would engineer a significant yuan devaluation as it endures the slowest economic growth in a quarter-century.

Right before the formal talks began, Mr. Zhou spoke forcefully in English. “There is no basis for persistent [yuan] depreciation from the perspective of economic fundamentals,” he told a forum of investors. Then, the premier addressed structural-reform plans during a video conference with the G-20 on Saturday.

Still murky after the G-20 is how Chinese authorities are actually managing the yuan.

Officially, the central bank attaches the yuan’s value to as many as three baskets of currencies of its trading partners—though Mr. Zhou told reporters Friday that among those, the dollar remains the most important, indicating the central bank continues to seek flexibility.

The basket model itself is a risk because it lacks transparency, and appears to provide opportunities for Beijing to cast blame elsewhere if the yuan falls, said David Loevinger, the U.S.’s former Treasury representative in China and now a fund manager at TCW in Los Angeles. Since the baskets include the euro and the yen, as well as the dollar, Mr. Loevinger said, China may now be trying to insulate itself from blame for any future currency turmoil by signaling, “Europe and Japan, you depreciate, we’ll depreciate.”

The reserves erosion may ultimately trump other concerns. If they continue to slip away, said Arthur Kroeber, managing director of Beijing research firm Gavekal Dragonomics, the question becomes, “frankly, how do you get out of this?”