What does she mean no guarantee??? This entire time it's been hammered into our skulls how...

What does she mean no guarantee??? This entire time it's been hammered into our skulls how important brides are. Even FL wanted an ayakashi and was jealous of her sister and friend because she saw how loved the brides were and seemingly nothing could break their bond. Yet now she turns around and says there's no guarantee, what does that mean??????!!!!!!