@Talismaster I remember machiavelli said something similar to that. "If you want to remove your opponent, do it in one swoop so that people see you in the good views , while fails to do so or you did it twice, people will see you as a dictator and a mass murderer" or something similar to line like that.
@SotiCoto She did say "final decision"
She is telling him to make a decision to begin with. If he doubts based solely on what she wants, it would be the same as her making the decisions, when what she likes about him is precisely being decisive.