Represented two clients with conflicting interests. John reasonably believes that he can successfully represent both clients. Both of the clients have provided written consent as to the representation and the representation is not prohibited by law.

Acceptable.

Explanation:

The paragraph described above is fully acceptable under the law and represents legal form to resolve a conflicting situation between two clients. That is, John can successfully represent both clients who have conflicting interests, provided that both clients provide written consent to representation and representation is not prohibited by law.