How is he forgetting his own words though
The dialogue and expressions on pages 36 and 37 seem to suggest that Gozu does remember, and Anko knows that he remembers, but he's just acting "cool" about it and avoiding Anko's romantic advances.
The way I understand the situation so far is: Gozu is aware of Anko's true form, and Anko knows that he knows, but she is hiding her true form simply because she wants to appear cute in front of him. Gozu is just allowing Anko to do whatever makes her feel most comfortable about herself.
The most curious line is when Anko(?) asks, "You thought it was a man, didn't you?", and "Why is that?".
I'm also not entirely sure about who says, "I will keep waiting for you no matter how long it takes.". It seems like it's a continuation of Gozu's lines (i.e.: "If you can't love your own appearance, then I will love you. [...] I will keep waiting for you no matter how long it takes.", for Anko to learn to love herself).