  In this article we study the rare B-meson decay via two on-shell
almost-degenerate Majorana Heavy Neutrinos, into two charged leptons and two
pseudoscalar mesons ($B^{\pm} \to D^0 \ell^{\pm}_1 \ell^{\pm}_2 \pi^{\mp}$). We
consider the scenario where the heavy neutrino masses are $\sim 2$ GeV and the
heavy-light mixing coefficients are $|B_{\ell N}|^2 \sim 10^{-5}$, and evaluate
the possibility to measure the CP-asymmetry at Belle II. We present some
realistic conditions under which the asymmetry could be detected.
