Why a man keeps double face?

Fear. We are afraid that if we fully reveal our feelings, we will be hurt. So we are afraid to allow ourselves to be vulnerable. And if we reveal our thoughts and beliefs, we fear that we may be ridiculed and rejected.

Sometimes when we reveal our feelings and our thoughts, we do get hurt. E.g. if you tell someone you love them, and they do not love you, and even avoid you afterward, that is painful. On the other hand, by expressing our love to another we allow the possibility of great joy when they reveal to us that they love us as much as we love them! So with risk, there can be great reward.

As we become more confident and accepting of ourselves, we become less concerned how others view us. Then we rid ourselves of our mask and show our true selves. We will be amazed how many people love and accept us for who we really are.

For so many reasons most of the you might be knowing but what I feel is double gaining ( gain from both sides)

We don't trust people with our inner self. We instead use the work face, play face, poker face, whatever face we need for the moment.