Many people around us give wrong or vague answers to our questions. When you ask them, "Did you eat?" often they might answer "I have a bit of indigestion", "I'm not really hungry right now" or "I'll eat later." Is it not easier just to answer either "Yes, I ate" or "No, I didn't eat"? With this attitude and habit of answering, you may let important conversations go astray. To the extent that your heart becomes sincere you can focus on what is said by the other party. You will be able to consider what the other party wants to know and you will be able to reply with genuine and sincere responses to the questions asked.
"But let your statement be, 'Yes, yes' or 'No, no'; anything beyond these is of evil." (Matthew 5:37)