Answer
Since the difference between electronegativity of $Na$ and $H$ is greater than difference between $S$ and $H$, $NaH$ has a greater degree of ionic character than $H_2S$.
Work Step by Step
Since the difference between electronegativity of $Na$ and $H$ is greater than difference between $S$ and $H$, $NaH$ has a greater degree of ionic character than $H_2S$.