Relation predicted by TNG-Cluster and obtained via forward-modelling between best-fit velocity dispersion and best-fit temperature of the ICM in the central regions of Perseus-like clusters in comparison to the Hitomi observation of Perseus (Hitomi Collaboration 2016). These values are obtained by fitting mock spectra in the [6.4−8] keV band of 30 simulated cluster cores seen in a random orientation with 100 ks exposures with XRISM Resolve. The blue solid line gives the median value across the Perseus-like sample. In the background, we indicate with dashed lines the ratio P_{non − thermal}/P_thermal, which is the ratio of motion-induced non-thermal pressure to thermal pressure (see text for details). TNG-Cluster naturally returns values for the LoS velocity dispersion in Perseus-like cores that are consistent with those derived for Perseus, with a low contribution of gas motions to the non-thermal compared to thermal pressure.