Assertiveness is very much a question of a right relationship with the self.
When we argue, we try to make ourselves right and the other person wrong. But, instead of helping, this urge to polarise actually perpetuates conflict. True happiness lies in being happy to be neither right nor wrong, to just be.
Arguments escalate because we cannot wait to get our words in. Simple accepting that the other has spoken is a powerful tool for peace.
Arguments happen when behaviour, actions or perspectives diverge. The divergence causes conflict, and the conflict affects the communication. One of the best ways to start