Rephrase PyUnicode_CompareWithASCIIString() documentation
diff --git a/Doc/c-api/unicode.rst b/Doc/c-api/unicode.rst
index fd36356..6783f65 100644
--- a/Doc/c-api/unicode.rst
+++ b/Doc/c-api/unicode.rst
@@ -1063,8 +1063,9 @@
.. c:function:: int PyUnicode_CompareWithASCIIString(PyObject *uni, char *string)
Compare a unicode object, *uni*, with *string* and return -1, 0, 1 for less
- than, equal, and greater than, respectively. *string* is an ASCII-encoded
- string (it is interpreted as ISO-8859-1).
+ than, equal, and greater than, respectively. It is best to pass only
+ ASCII-encoded strings, but the function interprets the input string as
+ ISO-8859-1 if it contains non-ASCII characters".
.. c:function:: int PyUnicode_RichCompare(PyObject *left, PyObject *right, int op)