If everything fails and she still clings to him, I must play my last card, or rather you must play it for me.

I shall leave with you a sealed letter which you are to give her if everything else fails.

Do it before she sees Ratcliffe a second time.

See that she reads it and, if necessary, make her read it, no matter when or where.

No one else must know that it exists, and you must take as much care of it as though it were a diamond.