  Recent high-resolution X-ray spectroscopy has revealed that several supernova
remnants (SNRs) in the Large Magellanic Cloud (LMC) show unusually high
forbidden-to-resonance ($f/r$) line ratios. While their origin is still
uncertain and debated, most of these SNRs have asymmetric morphology and/or
show evidence of interaction with dense material, which may hint at the true
nature of the anomalous $f/r$ ratios. Here we report on a detailed spectral
analysis of an LMC SNR J0453.6$-$6829 with the Reflection Grating Spectrometer
(RGS) onboard XMM-Newton. We find that the $f/r$ ratio of O$~$VII
($=1.06^{+0.09}_{-0.10}$) is significantly higher than expected from the
previously-reported thermal model. The spectrum is fairly explained by taking
into account a charge exchange (CX) emission in addition to the thermal
component. Analyzing archival ATCA & Parkes radio data, we also reveal that
H$~$I cloud is possibly interacting with J0453.6$-$6829. These results support
the presence of CX in J0453.6$-$6829, as the origin of the obtained high $f/r$
ratio. Although a contribution of the resonance scattering (RS) cannot be ruled
out at this time, we conclude that CX seems more likely than RS considering the
relatively symmetric morphology of this remnant.
