It is the difference between Oedipus doing everything he can to avoid killing his father and marrying his mother, and doing it anyway because it is fated. Or Oedipus turning on his father when he hears he is going to kill him anyway sometime in the future. In the first case Oedipus was forced, but in the second he is not.
In other words. Most people will try to avoid their fate if they find it unacceptable, but then fate steps in and forces the issue. Wanda is different, she deliberately attempts to fill the role fate lays out for her, without resisting.