  AMoRE-II aims to search for neutrinoless double beta decay with an array of
423 Li$_2$$^{100}$MoO$_4$ crystals operating in the cryogenic system as the
main phase of the Advanced Molybdenum-based Rare process Experiment (AMoRE).
AMoRE has been planned to operate in three phases: AMoRE-pilot, AMoRE-I, and
AMoRE-II. AMoRE-II is currently being installed at the Yemi Underground
Laboratory, located approximately 1000 meters deep in Jeongseon, Korea. The
goal of AMoRE-II is to reach up to $T^{0\nu\beta\beta}_{1/2}$ $\sim$ 6 $\times$
10$^{26}$ years, corresponding to an effective Majorana mass of 15 - 29 meV,
covering all the inverted mass hierarchy regions. To achieve this, the
background level of the experimental configurations and possible background
sources of gamma and beta events should be well understood. We have intensively
performed Monte Carlo simulations using the GEANT4 toolkit in all the
experimental configurations with potential sources. We report the estimated
background level that meets the 10$^{-4}$counts/(keV$\cdot$kg$\cdot$yr)
requirement for AMoRE-II in the region of interest (ROI) and show the projected
half-life sensitivity based on the simulation study.
