Translation:That restaurant is romantic.
I agree, the version with “very” should be accepted, but the version without it is not wrong. You could even make the argument that it’s more default because the ”very” reading requires 很 to be emphasised. Without that emphasis it is basically just a placeholder (adjectives need an adverb of degree (a word like “very, really, completely” etc.) if they are in the place of the main verb. 很 is the weakest of these, so weak that it really doesn’t mean any increase in intensity unless stressed).
浪漫 is an example of an early 20th-century Sino-Japanese coinage imported into both Chinese and Korean. In Japanese, it's rouman or roman, man having a broad meaning that includes 'extravagance'. 浪 can mean 'wave' and 'wander', and the idea of wandering is a major theme of German romanticism (die Wanderung).