love story vs romance

love story and romance both are nouns.

Word	Noun	Adjective	Verb	Adverb
love story	Yes	No	No	No
romance	Yes	No	Yes	No

As nouns, love story and romance are synonyms defined as:

love story (noun)	romance (noun)
a story dealing with love	an exciting and mysterious quality (as of a heroic time or adventure)
	a novel dealing with idealized events remote from everyday life
	a story dealing with love
	a relationship between two lovers

love story (verb)	romance (verb)
	tell romantic or exaggerated lies
	talk or behave amorously, without serious intentions
	have a love affair with
	make amorous advances towards