Food for thought: Does your child not disclose their real feelings because they think you would disapprove of them? Children no matter what they say, like to be approved of. Let us say you are a high powered lawyer and you feel cheerleading is beneath you, so you tell your daughter when you see a cheerleader, "Why would anyone want to be a cheerleader? It is not like they do anything useful. All they do is jump and down like idiots." Now if your daughter has a secret dream to be a cheerleader, do you think she is going to share this idea with a mother who feels that way? So if she secretly tries out for the squad and does not make it, why would she tell you she is depressed about it? You might just tell her it was a big waste of time anyway. Never belittle a child's dream, even if it is not a dream you would choose for yourself. Remember your child is not you.
Kids can hide their feelings from parents for different reasons. They feel they will not understand; they do not think their parent can help solve the problem; what is the point; the child does not want to be a burden (such as his mother is going through a divorce with his father and she is already stressed out so why trouble her with X.). Watch for signs of loneliness, anger or depression. Does your child hide out in their room talking to no one? Do they spend a lot of time alone at school? Do they slam doors repeatedly in frustration? Do they weep for no apparent reason? You can not make your child talk to you. But you can reach out to them.
Last remark: I have heard a few parents complain, "I was close to my mother growing up and shared what was going on in my life with her, so why doesn't my child do the same thing with me?" Answer: Your child is not you. Maybe you’re extroverted where your child tends to be shy and private.