A protest is the act of saying or showing publicly that you object to something.
抗议 The opposition now seems too weak to stage any serious protests against the government.
If you protest that something is the case, you insist that it is the case, when other people think that it may not be.
断言 "I never said any of that to her," he protested. “我从来没有对她说过那种话,”他断然否认。