So a few weeks ago, Carmen came up to me and said she was moving, I was like see ya but she decided to stay. A week or 2 ago, she came up to me again, this time, thinking the other one didn't work, I picked please stay, guess what happened this time. =.= Has this ever happened to you?
When your villager approaches you and says they're moving, if you tell them to stay, 100% of the time they will. If you say Move, 50% of the time they will move. So, you just got bad luck the first time.