2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/139102We investigate dominant late-time tail behaviors of massive scalar fields in nearly extreme Reissner-Nordström background. It is shown that the oscillatory tail of the scalar fields has the decay rate of $t^{-5/6}$ at asymptotically late times. The physical mechanism by which the asymptotic $t^{-5/6}$ tail yields and the relation between the field mass and the time scale when the tail begins to dominate, are discussed in terms of resonance backscattering due to spacetime curvature.18 pages, 1 figure, accepted for publication in Physical Review DGeneral Relativity and Quantum Cosmologytext