Re: Restrained sex.. how to get started?
While I agree with the all the advice on talking and a safe word, if she is still timid about the idea, there may be a way to ease her into the game.
I suggest you DON'T restrain her to start with. Instead, give her something to small hold, something that requires both hands, something that she can't bend or break. Perhaps a length of wooden dowel or a large serving spoon, for example.
The game would be she MUST hold that object with both hands as an introduction to the game. This would limit her ability to move without actually binding her.
If she finds that pleasurable, THEN you can go to the light/loose restraints. I would start with the feet, leaving the hands free, as she will feel much less confined that way.
If that goes well, then move to the loose hands restraints. This will allow the trust to be built in a safe and controlled manner.