Mrs. Linde believes she will return with Krogstad, because there was a time when Krogstad would do anything for her, so she believes that in the name of the old days, Krogstad will return with her if she asks. This can be seen in the text at the moment when Nora asks Mrs. Linde not to meet Krogstad because he can hurt her, but Mrs. Linda tells the girl not to worry because there was a time when Krogstad would do anything for her.
