If the difference in electronegativity is less than 0.4, the bond is considered non-polar.
And if the electronegativity is higher than 0.4, the bond is polar, however if the electronegativity is 1.8 and high the bond is considered ionic.
Lets calculate the electronegativities of H2S and H2O
For H2S: H have electronegativity of 2.1 and S have electronegativity of 2.5.
2.5-2.1 =0.4
For H2O: H electronegativity is 2.1 and O electronegativity is 3.5.
3.5-2.1 = 1.4
Therefore H2O is highly polar than H2S.