Love Is Only Love was composed by Jerry Herman for his musical show Mame. However, it was cut before the opening, and was later sung by Barbra Streisand in the film version of Hello Dolly.

It's a pretty song that I think Streisand schmaltzes up badly. But Marian Montgomery has a decent version on YouTube, albeit with an overdone background.
https://www.youtube.com/watch?v=Go7gDx-0P24

I took some liberties with the harmony, as usual, and I've included the original song's coda, which Montgomery doesn't sing.

Here it is in Montgomery's key of G major. Streisand sings it in C, and I have a lead sheet for it in D.

Love Is Only Love-Rev JE - Jerry Herman

Cheers,
Jer