'Twfaced' actions destabilize bilateral ties

"Two faced" actions indeed can seriously destabilize bilateral ties.

In the context of diplomatic relations
   Lack of trust
     When a country engages in two faced behavior, such as publicly expressing support for another country's sovereignty and territorial integrity while privately colluding with separatist forces in that country, it completely undermines the foundation of trust. For example, if a country verbally advocates for peaceful co existence with its neighbor but at the same time provides covert military or financial support to anti government elements within that neighbor, the trusting relationship built on diplomatic protocols and international law will be severely damaged.
   Policy incoherence
     Two faced actions often lead to inconsistent policy implementation. A state may promise economic cooperation and mutual benefit in one aspect but then impose hidden trade barriers or discriminatory policies. This incoherence not only confuses the partner country but also disrupts the normal rhythm of bilateral economic and trade exchanges. For instance, a country might claim to support free trade with a developing nation but then use non transparent technical regulations to restrict the latter's exports.

   Damage to international cooperation mechanisms
     In international relations, many issues require multilateral or bilateral cooperation. Two faced actions can paralyze these cooperation mechanisms. If a country is duplicitous in climate change cooperation, for example, by publicly agreeing to emission reduction targets but privately shirking its responsibilities, it not only harms the bilateral cooperation with countries that are sincerely committed but also undermines the global efforts to address climate change.

In other areas of bilateral relations such as cultural and people to people exchanges
   Negative impact on people to people relations
     If a country shows two faced attitudes towards the cultural exchanges with another country, it can dampen the enthusiasm of the two peoples for mutual understanding. For example, on the one hand, promoting cultural exchange programs, but on the other hand, spreading negative and false information about the other country's culture through certain media channels. This will create misunderstandings and hostilities among the general public of both sides, which in turn affects the overall bilateral relations.