In the scene that takes place the morning Viola is supposed to go to Greenwich to meet the queen, she is arguing with Will in her bedroom. She says to Will, "...the river divides us, and I must marry Wessex a week from Saturday." When she says, "I must marry Wessex," it looks like she's saying, "I will marry Wessex," or something like it. Her mouth doesn't look like it's making an "s" sound.