So Yeon said in the bri that she didn't give it too much deep thoughts as she assumed (maybe unconsciously) that they would likely to continue since it has been good but when she saw her hubby's serious look and heard his words about scared, suddenly she was hit by reality.
She told Si Yang that no matter what happens, they had been happy these 100 days and she feels blessed.
Si Yang asked if she really felt blessed and she said yes.
He then asked her if he would become someone (a man) unforgettable in her life?
So Yeon : " You surpassed even that"!