sperk

"Женщина не так поймет, если уже не поняла."

I may be wrong, not having watched the show and all, or because the transcript can be inaccurate, but how it is I see this line as a deliberate grammatical non sequitur (if this is the right word for it).

This is what I think it means with all the context included:
"She will understand you the wrong way, she will wrongly think that you are interested in her. That is, if she didn't already understand that you are interested in her."
This is the dog being ironic.