Updating a Reference as a Class Member

I'm pretty sure I'm misunderstanding references.

In the code below, I'd like to initialize A to have a state, but at some time in the future, when I call init (registering a B object to A), I'd like stateB variable to show the value of the B state.

I can do this by making stateB a pointer, then initializing some memory in A's constructor and setting it to the default, then moving this pointer and deleting the memory when calling init.

Can I do this without stateB being a pointer by changing the reference of stateB to be b->state?

Class A {
public:
  int stateB = 0;
  B *b = nullptr;
  void init(B *b) {
     &state = &b->state;
  }
}

class B {
public:
  int state = 1;
}