if you have a problem you that you shouldn't be doing, reason can be tricked by thinking that the bad things are good but conscience is when you know it's wrong.
Trust in yourself, because the common and reasonable way will lead to regret.
Explanation:
Well the definition of conscience is being aware or more specifically "aware of and responding to one's surroundings" or your inner mind. and the definition of reason is " cause, explanation, or justification for an action or event." Now that we know the definition we can move onto the question. Well I believe its trying to tell people to believe in their conscience you may feel this in your stomach or just get a tingling feeling because following the path that may seem reasoning to you can be often misleading and regretting.
Actually venting problems with the person may help them understand that you dont like or wont tolerate his or her behavior and can help understand not to do it in the future with other peers. It's never good to be shy and scared please speak up.