How will Iori convince Mi-chan to want to stay as a human?
I think she just wants him to stop being flaky and indecisive and to take direct action towards it. Iori took a step in the right direction by finally choosing something but now he has to follow through and take action.
Im not good at explaining this stuff... its like she's saying "make a choice and mean it. Make sure you arent going to regret it and be so confident in your choice you make me think thats the only correct option".
She isnt exactly wrong in that either. Its a massive permanent desicion so she has to make sure the man she picked made the correct one. Though she could be better at communicating it I suppose.
Its like she thinks "if he doesnt get it by the time limit im better off as a cat and not having to worry about anything anyways"