Setsuko felt guilt to her dead husband and was hesitant to move forward, but the cat facilitates the spirit of her husband to speak with her and tell her it's alright and he wants her to move forward and find happiness. Don't worry, he'll make everything work out for her. Setsuko then tries to tell him the truth about her being previously married and rejuvenated, but reality was changed so there was no prior marriage listed on records anymore (And presumably a retconned birth date etc.) so she was able to move forward with marriage.