Understandably, so many cut-off parents do not know what their child is really thinking or feeling. I am here to tell you three things that your alienated child wish you knew. And this comes from the heart, since I was once an alienated child myself.
1. I don't want to have to choose sides.
Children love both parents. When a divorce takes place, this does not change. They don't want to be left with feeling they have to choose sides, or make decisions that their parents should be making. And yet once a parent puts them in that position, they will feel they have to make those decisions, and therefore continue to do so. This is why many children feel empowered to choose parenting schedules, communication with a parent, etc. Children need healthy rules in order to navigate life, and they like structure and to occasionally make decisions--but ones that children should be making (i.e., maybe an activity, what to have for dinner (with exceptions), etc)--not what the parenting schedule should be. They might have a desire to stay at one parent over the other's, maybe the other parent lives further away and are away from friends, school, etc. However make sure it isn't what you want. Make it work with your co-parent so it's easier on the child, take you out of it.
2. I don't like behaving negatively towards you.
Regardless of how terrible an alienated child may act out towards a parent, deep down they do not want to act that way. Ask me how I know! Many reunited children admit that they feel guilty over how they treated their parent. They admit that they exaggerated things or even flat out lied. I would feel terrible after some of the things I said and did to my dad, yet I still did it. It's a cry for help, and many parents are not hearing it correctly. Don't try to get defensive, either. Remain in your authentic place, from a place of unconditional love.
3. I don't like when either parent talks about the other.
This should be obvious, and yet it happens far too often. Parents who are in a high-conflict dynamic can't help themselves but try to lift themselves up or seem like the better parent. So what is the first [unconscious] things that comes to mind? Put the other parent down, of course! When you are not confident as a parent, in the way you're handling divorce, or if you're upset at how your children behave towards you, then oftentimes that gets communicated through denigrating the other parent. And despite possible complaints children may share about their other parent, ask yourself if they are coming from you or them. And maybe it's both. That doesn't mean you can egg on their complaints. It doesn't feel good for a child to hear things about the other parent, and especially if it's regarding the other parent's role as a spouse. That has nothing to do with them. This is most common with affairs. If they are still there for their child, then that doesn't always make them both a crappy spouse and parent, by association. While we don't want to create an illusion that parents are perfect (because they are not), we do not have to resort to downright negativity and denigration.
...Being cut off from a child, whether to the full extent or just marginally, is painful and oftentimes confusing. The main thing to remember is that your child feels no different. It is important to always keep in mind that there are things they are feeling that they may never express to you outright or directly. Have compassion and empathy for them, and always seek support if you are struggling in that realm.