diff --git a/docs/x509.rst b/docs/x509.rst
index 39df4a0..afc9620 100644
--- a/docs/x509.rst
+++ b/docs/x509.rst
@@ -460,7 +460,7 @@
 
         :type: bool
 
-        This is asserted when the subject public key is used for verifying
+        This purpose is set to true when the subject public key is used for verifying
         digital signatures, other than signatures on certificates
         (``key_cert_sign``) and CRLs (``crl_sign``).
 
@@ -468,7 +468,7 @@
 
         :type: bool
 
-        This is asserted when the subject public key is used for verifying
+        This purpose is set to true when the subject public key is used for verifying
         digital signatures, other than signatures on certificates
         (``key_cert_sign``) and CRLs (``crl_sign``). It is used to provide a
         non-repudiation service that protects against the signing entity
@@ -481,48 +481,48 @@
 
         :type: bool
 
-        This is asserted when the subject public key is used for enciphering
-        private or secret keys.
+        This purpose is set to true when the subject public key is used for
+        enciphering private or secret keys.
 
     .. attribute:: data_encipherment
 
         :type: bool
 
-        This is asserted when the subject public key is used for directly
-        enciphering raw user data without the use of an intermediate symmetric
-        cipher.
+        This purpose is set to true when the subject public key is used for
+        directly enciphering raw user data without the use of an intermediate
+        symmetric cipher.
 
     .. attribute:: key_agreement
 
         :type: bool
 
-        This is asserted when the subject public key is used for key agreement.
-        For example, when a Diffie-Hellman key is to be used for key
-        management, then this bit is set.
+        This purpose is set to true when the subject public key is used for key
+        agreement.  For example, when a Diffie-Hellman key is to be used for
+        key management, then this purpose is set to true.
 
     .. attribute:: key_cert_sign
 
         :type: bool
 
-        This is asserted when the subject public key is used for verifying
-        signatures on public key certificates. If this bit is asserted then
-        ``ca`` must be true in the :class:`BasicConstraints` extension.
+        This purpose is set to true when the subject public key is used for
+        verifying signatures on public key certificates. If this purpose is set
+        to true then ``ca`` must be true in the :class:`BasicConstraints`
+        extension.
 
     .. attribute:: crl_sign
 
         :type: bool
 
-        This is asserted when the subject public key is used for verifying
-        signatures on certificate revocation lists.
+        This purpose is set to true when the subject public key is used for
+        verifying signatures on certificate revocation lists.
 
     .. attribute:: encipher_only
 
         :type: bool
 
-        The meaning of this bit is undefined in the absence of the
-        ``key_agreement`` bit.  When this bit is asserted and the
-        ``key_agreement`` bit is also set, the subject public key may be
-        used only for enciphering data while performing key agreement.
+        When this purposes is set to true and the ``key_agreement`` purpose is
+        also set, the subject public key may be used only for enciphering data
+        while performing key agreement.
 
         :raises ValueError: This is raised if accessed when ``key_agreement``
             is false.
@@ -531,10 +531,9 @@
 
         :type: bool
 
-        The meaning of this bit is undefined in the absence of the
-        ``key_agreement`` bit.  When this bit is asserted and the
-        ``key_agreement`` bit is also set, the subject public key may be
-        used only for deciphering data while performing key agreement.
+        When this purposes is set to true and the ``key_agreement`` purpose is
+        also set, the subject public key may be used only for deciphering data
+        while performing key agreement.
 
         :raises ValueError: This is raised if accessed when ``key_agreement``
             is false.