  Multi-wavelength observations of active galactic nuclei (AGNs) often reveal
various time scales of variability. Among these phenomena, "changing-look AGNs"
are extreme cases where broad emission lines become faint/bright or even
disappear/emerge between multi-epoch observations, providing crucial
information about AGN internal structures. We here focus on "changing-state"
AGNs, specifically investigating the transition of optical spectra over years
to tens of years. Based on the axisymmetric radiation-hydrodynamical
simulations (Paper I) for the gas dynamics within the dust-sublimation radius,
we investigate the spectral properties of ionized gas exposed to the radiation
from an AGN with a 10^7 Msun supermassive black hole. We find significant
time-dependent variations in the Balmer emission lines by utilizing
post-process pseudo-three-dimensional calculations and the spectral synthesis
code CLOUDY. The equivalent width of Halpha and Hbeta changes by a factor of 3,
or the emission lines even disappear during 30 years for the same viewing
angle. The time-dependent behaviour arises primarily from gas dynamics,
particularly the formation of non-steady, radiation-driven outflows within the
innermost region of the disc (r <10^-3 pc). The intricate interplay between
non-spherical radiation sources at the core of AGNs and the dynamic behavior of
gas within the dust sublimation radius gives rise to radiation-driven outflows.
This non-steady outflow potentially contributes to the observed variability in
Balmer line emissions over multi-year timescales in certain AGNs.
