We present the stellar and gaseous kinematics of an Sb galaxy , NGC 3223 , with the aim of determining the vertical and radial stellar velocity dispersion as a function of radius , which can help to constrain disk heating theories . Together with the observed NIR photometry , the vertical velocity dispersion is also used to determine the stellar mass-to-light ( M/L ) ratio , typically one of the largest uncertainties when deriving the dark matter distribution from the observed rotation curve . We find a vertical-to-radial velocity dispersion ratio of \sigma _ { z } / \sigma _ { R } = 1.21 \pm 0.14 , significantly higher than expectations from known correlations , and a weakly-constrained Ks-band stellar M/L ratio in the range 0.5–1.7 , at the high end of ( but consistent with ) the predictions of stellar population synthesis models . Such a weak constraint on the stellar M/L ratio , however , does not allow us to securely determine the dark matter density distribution . To achieve this , either a statistical approach or additional data ( e.g . integral-field unit ) are needed .