[cprncus]

I don't think your clear statement means anything, legally. What matters is the name similarity. If a soda company was called Pepsee and then stated, "We are not Pepsi, a registered trademark of the Pepsicola Corporation", they would still get sued into oblivion.

IANAL, but it strikes me as at least arguable as "confusing similarity" (http://en.wikipedia.org/wiki/Confusing_similarity). Do you want to find out the answer in court, or could you just change the name of your app to something obviously different from "plenty of fish"? Like "The Gorton Fisherman of Love". No, don't do that.

(I'm curious if there is any additional concern about making a client for something without permission)