Assertiveness is the ability to express your thoughts and feelings, and to put forth your opinions − even if contradicting − in such a way that they clearly state your point of view while respecting others' feelings and opinions.
It makes you speak honestly and directly about your thoughts, feelings, and opinions without offending the listener(s), or hurting their sentiments.
It makes the other person more comfortable to have a conversation with you, as he feels that his opinion is also being given equal importance. This makes him more forthcoming and open to share his thoughts with you.
It makes you confident to exercise more control over your life in difficult situations, rather than blindly following instructions and directions of other people.
An assertive person would normally display the following traits −