The Belle II experiment at the SuperKEKB collider is a major upgrade of the KEK “B factory” facility in Tsukuba, Japan. The machine is designed for an instantaneous luminosity of [Formula: see text], and the experiment is expected to accumulate a data sample of about 50 ab[Formula: see text]. With this amount of data, decays sensitive to physics beyond the Standard Model can be studied with unprecedented precision. One promising set of modes are physics processes with missing energy such as [Formula: see text], [Formula: see text], and [Formula: see text] decays. The [Formula: see text] decay provides one of the cleanest experimental probes of the flavour-changing neutral current process [Formula: see text], which is sensitive to physics beyond the Standard Model. However, the missing energies of the neutrinos in the final state makes the measurement challenging and requires full reconstruction of the spectator [Formula: see text] meson in [Formula: see text] events. This report discusses the expected sensitivities of Belle II for these rare decays.