I can say more about what it isn't than what it is. What something isn't is generally easier, so this comes as no surprise.
It's not just about trust. For example, I can trust Cindy with anything and everything. I can even trust her with my honor; she can make decisions for me and I will abide by them. I've trusted some with my life but Cindy is the only one I've ever trusted my decision making ability with.
It's not just about service. Both Cindy and I serve each other and those we love regularly with all our hearts and minds. We service each other regularly as well but that's different. :)
It's not just about submission and allowing someone else to make my decisions for me. I don't want to just be told what to do. If something like this happens and I don't like it, I'll find some way to comply completely with what is asked but twist it completely around.
I would want to be an advisor or possibly a castellan. I don't mind doing what people tell me to do but the person has to seem competent to me and I need to either see why or I need to trust them.
So, this tells me what it isn't but I'm still only a little closer to what it is.