How do you say nice or lovely or beautiful couple in Japanese?

In Japan, we usually just say, " かわいいカップル！" which is pronounced as, "Kawaii kappuru!" (kah- wàh ee kah pu- roo) which is basically slang for " Cute couple!"

The other way to say it is, " お似合いのカップル！" pronounced, "Onai no kappuru!" (Oh- nâh ee noh kah pu- roo). This is more like, "Perfect couple" though.