CBA boss Matt Comyn has taken another step towards simplifying the business operations of the country's largest bank after offloading the group's minority stake in a Chinese life insurance joint venture.Japanese insurer Mitsui Sumitomo Insurance has agreed to buy CBA's 37.5 per cent interest in the Shanghai-based BoComm Life company for A$668 million (RMB3.2 billion).If the deal is completed, CBA will book a post-tax gain of about $450 million because the carrying value of the BoComm stake was only $150 million in the most recently published financial accounts of the group.However, there are concerns that regulatory approvals for the sale could be stalled owing to Australia's deteriorating diplomatic relationship with the Chinese Government.The deal with Mitsui Sumitomo requires sign-offs from China's banking and corporate regulators before the sale proceeds can be repatriated to Australia and included in CBA's Tier 1 capital base.State-owned Chinese newspapers this week have called for trade retribution against Australia in the wake of deepening political tensions between the Turnbull Government and the administration of President Xi Jinping.The relationship has soured to such a low point that the Chinese government has denied entry visas for several Australian government ministers in the past month.While relations are worsening at a government level, the public narrative is markedly different for interactions between the two countries' central banks.In March, the RBA and the Peoples' Bank of China renewed a 200 billion yuan currency swap arrangement aimed at facilitating bilateral trade settlements over the next three years.Reserve Bank governor Philip Lowe yesterday weighed into the diplomatic controversy in a speech he gave to the Australia-China Relations Institute in Sydney.Lowe spent most of his address highlighting China's economic and cultural importance to Australia."The deepening relationship has also benefited China in many ways," Lowe told the institute."This means that both countries have a strong interest in managing this important relationship well."It is in our mutual interests to do this."Lowe deftly touched on how the nature of the relationship could sometimes turn awkward."We will, of course, have differences from time to time, but we will surely be better placed to deal with these if we understand one another well," he said. "Building strong connections across business, finance, politics, academia and the community more generally is important to deepening this understanding."CBA's Comyn will no doubt be hoping that the goodwill displayed between the two central banks might help to curb any politically inspired regulatory move to jumble the BoComm transaction.Comyn needs the cash.APRA has already called on CBA to add $1 billion to its Tier 1 capital base and the company also has to make additional provisions to cover a string of hefty fines likely to flow from compliance failures.The bank has also been hit with various class actions stemming from its compliance problems, which may erode the bank's capital position further.CBA scrip yesterday fell to its lowest level in five years as negative sentiment about the company's earnings trajectory continued to weigh on stock.The share price closed down 44 cents to $69.81 on average turnover.It