  In this work, we explore the hadronic coupling constants $G_{ZJ/\psi K}$,
$G_{Z\eta_c K^*}$, $G_{ZD^* \bar{D}_s}$ of the exotic states
$Z_{cs}(3985/4000)$ both in the pictures of the tetraquark states and molecular
states with the tentative assignments $J^{PC}=1^{+-}$ based on the rigorous
quark-hadron duality. Then we obtain the total widths $\Gamma_{Z_{cs}}^T
=15.31\pm 2.06\,\rm{MeV}$ and $\Gamma_{Z_{cs}}^M=83.51\pm21.09\,\rm{MeV}$,
which are consistent with the experimental data
$13.8^{+8.1}_{-5.2}\pm4.9\,\rm{MeV}$ from the BESIII collaboration and $131 \pm
15 \pm 26\,\rm{MeV}$ from the LHCb collaboration, respectively, and support
assigning the $Z_{cs}(3985)$ and $Z_{cs}(4000)$ to be the hidden-charm
tetraquark state and molecular state with the $J^{PC}=1^{+-}$, respectively.
