14350 (#18380)

Author: mpenkov

doc/source/whatsnew/v0.22.0.txt

@@ -27,6 +27,7 @@ Other Enhancements
 - :func:`MultiIndex.unique` now supports the ``level=`` argument, to get unique values from a specific index level (:issue:`17896`)
 - :class:`pandas.io.formats.style.Styler` now has method ``hide_index()`` to determine whether the index will be rendered in ouptut (:issue:`14194`)
 - :class:`pandas.io.formats.style.Styler` now has method ``hide_columns()`` to determine whether columns will be hidden in output (:issue:`14194`)
+- Improved wording of ValueError raised in :func:`Timestamp.tz_localize` function
 
 .. _whatsnew_0220.api_breaking:
 

pandas/_libs/tslib.pyx

@@ -1445,10 +1445,8 @@ cpdef array_with_unit_to_datetime(ndarray values, unit, errors='coerce'):
             else:
 
                 if is_raise:
-                    raise ValueError("non convertible value {0}"
-                                     "with the unit '{1}'".format(
-                                         val,
-                                         unit))
+                    raise ValueError("unit='{0}' not valid with non-numerical "
+                                     "val='{1}'".format(unit, val))
                 if is_ignore:
                     raise AssertionError