Assertiveness is the ability to express what is desired in an effective way achieving the greatest benefit without implying harm to others.
That is, getting others to understand what you want, your firm position at a certain point so that your rights are fulfilled without disrespecting the rights of others, to find the balance between a passive form of aggressive communication.
The best way to be assertive when communicating is to keep in mind what, when, where, how and to whom we say.
What do you mean? If you are not clear about this, you can not expect others to understand it, when will you say it is at the moment or is it better to wait (depends on the circumstances), where do you locate yourself in the space of time so that the message is understood, how are you going to say taking full advantage of the method in which you express it, and to whom we will tell it without losing your effort in people who can not fulfill the objective.
In this way you can achieve what I set out at the beginning, what you want, what you need and what corresponds to you, no more or less.
Thanks for reading my post, I hope you find it useful
@jguillermo