How we change what others think, feel, believe and do
Assertive behavior means standing up for your rights and expressing your truths in a way that neither shrinks from what you want to communicate nor assumes that they are the only valid truths.
Assertiveness also includes recognizing and respecting the equality, rights and truths of other people.
John, I don't like the way you said that.
I want to stay at home tonight.
I think Jane is not comfortable with the way you look at her.
Assertiveness can be understood in terms of what it is not: it is neither Aggressive behavior and Passive behavior. In both persuasion and defending against persuasive efforts, assertive behavior is a powerful tool.
The assumptions on which assertiveness is based are that:
A critical aspect of this is an assumption of equality, which leads to a respect for others that moderates, but does not obviate, the seeking to achieve one's own goals.
The result of assertive behavior is that you get much of what you want whilst retaining the respect of other people.
With respect to winning and losing:
In Transactional Analysis, the Adult uses assertive behavior and language, seeking equality rather than control or safety.