U.S. Secretary of Defense Chuck Hagel may well feel after wrapping up his four-day visit to China on Thursday that Beijing has become more frank with Washington and less hesitant to voice its dissatisfaction with some U.S. moves.

By inviting Hagel to tour the "Liaoning", China's sole aircraft carrier, and being honest about its grievances, China showed that it has nothing to hide.

Fan Changlong, vice chairman of China's Central Military Commission, on Wednesday denounced Hagel's recent remarks to ASEAN defense ministers and Japanese politicians over their territorial disputes with China as tough and biased.

He told Hagel before reporters that the Chinese people, including himself, were dissatisfied with such remarks.

The unusual harsh tone delivers a clear message: Beijing is resolved to defend its core interests, particularly territorial sovereignty, and will not allow any country to make waves.

The frankness is expected to reduce the possibility of miscalculation by other countries when they gauge China's red lines, and consequently reduce rashness in their China policy-making.

As a responsible player in regional and global affairs, China expects the United States to respect its core interests, but has been repeatedly disappointed by the latter's double-faced tactics.

Regardless of disagreements in various fields, both Beijing and Washington clearly know they are friends, not enemies, and a healthy U.S.-China relationship is a sine qua non for world peace and stability.

As Chinese President Xi Jinping has said, China sincerely hopes to establish a new type of major-country relationship with the United States, featuring mutual respect and common prosperity.

His U.S. counterpart, Barack Obama, has said the United States welcomes the rise of a stable, peaceful and prosperous China.

If hard-nosed politicians in Washington can understand Beijing's frankness and resolve better, China-U.S. ties will be more stable and the Asia-Pacific region will be more peaceful.