In both my personal and business life (just like in yours), communication is what helps us control things, it stimulates our thoughts, makes and sustains relationships, and can create hardships or a "smooth ride." The phrase, "my word is my bond," is one of those lines that has taught us about trust. The concept was in use long before contracts were enacted. In fact...even before there was paper to write them on. "If you don't mean it...don't say it," is another way of expressing the same idea. Now, don't get me wrong - there are things that are said in the heat of the moment that people really DON'T mean, they are words out of anger, hurt, or confusion. That's not what I'm addressing here.
When a person has time to think, the rational mind makes conclusions. It is then that you should be prepared to voice your thoughts - literally, or on paper. knowing that you've thought things through, researched and dissected, understood your strengths, weaknesses, and capabilities, taken mitigating situations into account, and recognized that what you've told (or will tell) people...is what they will often take as "your word" and repeat (if it's necessary - as in negotiations) to others. If you don't really mean what you say, are just saying it to placate someone, our worse...to deceive them - ultimately the "sticky situations" that will result may, in fact, derail your credibility and make you someone that others will refuse to deal with.
Trust is build on "saying what you mean" and "standing behind your word." There are certain behavioral types who will say things just to be liked. They'll volunteer, take on tasks, and say they'll help out...so that you'll like them. However, these same individuals (although they mean well) will often leave another person "hanging" because, in their desire to be liked, they've taken on so much that nothing can possible get done - at least on time and with the results necessary for success.
So my friends...be careful as to how, what, and when, you communicate. Make sure that you word is indeed "your bond." It is always better to say that you can't do something, don't know how to accomplish a task, that you don't have the proper information, or just don't know - than it is to attempt to bluff your way through. Ultimately...it will catch up to you! And...ruin your relationships, your credibility, and your reputation. Stay honest - it's always (as the saying goes) "the best policy." It will lead you down a much clearer, and cleaner, path.