Kind heart and Sincerity

lot of people keep doubting about how can sincere can help them to pass through their life. however, when we think deeply into the matter, I think that its truely important to have this two value in our life. Someone had said to me a long time ago, when we be nice with other people.. We don't have to tell them, I'm sincere with you. But let them feel on their own that we are sincere towards them. Pure sincere will be feels by the other party. We don't have to show it. But they will feel it on their own. Can you see now how both of this things are related together? Without kind heart, no sincere will happen. However, as I always mention in the previous post. No body in this would born to be purely bad guy and bad girl. I believe that there would be some kindness in their heart. We are human being provided with kindness in our heart. So lets not blame on the person only. But keep on thinking and examining the surrounding that may influence his emotion. Human being is a complex creature that God had ever create as we have the ability to manipulate things around us. For example, let we see how human being can manipulate metals for their own purpose such as for mold ring and so on. However, as I mention that human being is complex as they can manipulate thing around them to make something bad. lets take a look at the metal that had been used as example just now, human can make weapon from the metal that will guide to murder in their own society that would leave destruction behind their action. Some of us may asked, if its true that human being are full with love and kindness, why should this happen? I left that on your judgement and together we may discuss it further. So the big question among all is, how we can help to bring back the humanity among our people that had lack of the two values that I had mentioned above?