In a room of Lord Stanley's house, Stanley asks Sir Christopher Urswick to tell Richmond that, though he wholeheartedly supports Richmond, he cannot yet send aid because Richard has his son, George Stanley, and will behead him if he finds out about Stanley's betrayal. Stanley also tells Urswick that Elizabeth has gladly agreed to give Richmond her daughter's hand in marriage. Urswick lists the many nobles that have taken Richmond's side. They exit.
As Richard feared, Stanley is loyal to Richmond, not Richard, though Stanley is forced to conceal that loyalty to protect his son (note also the distinction here: Richard would never protect anyone, even his own children probably, had he had any). The news that Elizabeth will give her daughter's hand to Richmond shows that she was not a victim of Richard's speech after all and was only pretending to be won over by him. Richard's powers of persuasion, so all-powerful earlier in the play, have lost their potency now.