翻译：建立长期稳定的合作关系

to establish a stable long-term cooperation relationship

应该翻译的完整一些
We are willing to make a close cooperation for a long-term and stable relationship

来则广告:~~~
We welcome more overseas investment, new investment projects in China and long-term stable cooperation with us by the business communities around the world.
欢迎各国工商界进一步扩大对华投资,来华兴办新的投资项目,建立长期稳定的合作关系!

to establish a steady long-term cooperation