Being assertive do not only show that ure confident in urself but also prove that you are capable of handling ur inner feelings. In contrast, you wil be able to express and set up boundaries, understanding and respect with other people. A very healthy way to avoid conflict and arguments for sure. When you are assertive, You get ur needs and wants met without causing pain to others, attacking others in a psychological ways and purposely hurting others physically. Because when you are aggressive with another person, You will tend to hurt them and often create a conflict that may be hard to resolve. And to add things up, you don't realise ur conscience of ur action- Thus making you more selfish and making things harder for yourself and others. The result is often a lose-lose situation, comparing to a win-win contest if ure assertive. A way to measure whether you have been assertive is to check out how both of you are feeling right now in the relationship about the encounter( Be it bf:gf, parents:child, employee:employer, friend:friend, husband:wife etc). If both feel good about it, the chances are that you and the other person were assertive. But if either of u is feeling bad, then it is possible that one or both was aggressive. And it is also likely that the conflict is unresolved. Learning to speak up and explain ur doin, ur action, ur expression, ur reasons and so forth are those few things involved in being assertive. To clarify and to make others understand you - in a healthy form. It will benefit alot especially when talking to perhaps a person who is still-wounded. Because they would find it hard to accept when you reject them or giving a vague explaination to them. To learn to be confident, you must go through certain things. To belief in urself.. That is one thing, and to deal with the different type of people is another. Thus, this process will take time. But nonetheless if we are open with our mind, we will be able to deal it within a quick period of time. Its not necessary to go through a program, though the result will be very effective n worthwhile. But thinking of our everyday life, we interact and associate with others. Those you know- Friends, parents, siblings, colleagues. Those you dont- dealing with customers, talkin to strangers on net, handling new task with people from else where, recruiting ppl for the job, tour guides, lecturing n so on. These are all part of interaction. As you continue to do so, ur assertive level will grow. And that as well, is part of our life learnin skill.