Let's Just Be Friends is the seventh stage in Love is Sickness.
Line-up: You really only need Cameraman Cat, Jiangshi Cat, and Bahamut Cat (not True form).
Start off by spamming Cameraman Cats and upgrading your wallet until the first few Owlbrows are defeated. By then, you should have enough money for Bahamut Cat. Just keep spamming Cameraman and Jiangshi from here on out and you'll win.
I recommend having more meatshields such as Maximum the Fighter and Ramen Cat as it can be quite risky with just Cameraman and Jiangshi. Bringing Ururun Cat and using combos helps too.
Note: If the Owlbrows are not beaten before the St. Pigge the 2nd's arrive, you are almost guaranteed to lose very soon. I do not recommend sending other meatshields out as your wallet may not be able to sustain it. Instead, upgrade your Cameraman and try again.