indissoluble
adjective uk/ˌɪn.dɪˈsɒl.jə.bəl/ us/ˌɪn.dɪˈsɑːl.jə.bəl/
牢不可破的;稳定持久的
impossible to take apart or bring to an end, or existing for a very long time
an indissoluble bond of friendship 牢固的友谊纽带
The links between the two nations are indissoluble. 两国之间的关系是稳定持久的。