If the covid-19 appeared once, could it reappear anytime?
Frame challenge answer: you are jumping to the conclusion that they really hope the virus will "die out". But it's more likely they adopted those measures to slow its progression to a manageable degree. See e.g. this conceptual image from ECDC



Even if there are new outbreaks of COVID-19 in the future, when they happen is not irrelevant, as we could be much better prepared given the current/ongoing research on both (antiviral) treatments and possibly a vaccine as well.

Regarding the "meat" of the question, it's a matter of probabilities, not certainties. It was and is generally assumed that other [bat etc.] coronaviruses will jump hosts to humans in the future. 

Besides SARS, another (much) lesser known cross-species jump actually occurred in China in 2016 with SADS-CoV, which killed thousands of pig[let]s, but was not infectious to humans. Annoyingly enough for the Chinese pig farmers, SADS-CoV re-emerged in early 2019 despite the fact that there were no cases reported between May 2017 and January 2019.