Fair and Square - When you don't care much about what other will think then you become or express your feeling in a very fair and square manner.Most of the time people don't care what you are doing or its just our misconception that what other will think about it. Everyone is busy with their life and all they care about their looks, job, carrier, their achievements so if you think if something is good for you and it might not hurt any one in any way, However there will be someone at the corner of the world who will not be happy with you and not satisfied with whatever you are doing but you must not stop all of you to do is keep on moving ahead without caring much about people. At the end if you are happy and content nothing matters. 

Sentence-To be fair and square Murli has done everything he could do in order to excel in life but still he is not satisfied. 

Having an ace up the sleeve- you must have some advantages that you can rely upon if you are failed at some point. Advantages in a way suppose you have a job which pays you enough for your livelyhood but you want to try something in acting or movies. Then you must try it in free time or take a gap or leave and just go attend a seminar or give auditions so that you may get a chance but if you failed then you have a decent job that will pay you and you might try for the next time. I often suggest this to my friends and myself as well that don't be foolish by blindly taking risks because their are very less chances that it can turn out into golden opportunity. I am not saying that you shouldn't be taking risk but you must analyse every pros and cons of your decision because your life is dependent on it so be alert and clear before taking the risk in your life after this is real life and you won't get second chance. I am not pessimistic person but i analyze things and this is how you all should do because there are others life depend on you like yours younger sister brother,responsibility of your parents. 

Example :My friend kept silent in the entire meeting who knows he has ace up the sleeve.