I don't understand why "this relationship has a great value" is incorrect?
As a native English speaker, 'this report has great merit' would be the most appropriate when talking about a...um.. report.
Sometimes non-english speakers understand and translate french to english better...)) The meaning of that sentence is "this report is very valuable " ,as it gives us very important information.
That is one interpretation and it is a fair one. But it is certainly not the (only) meaning. It could just as easily refer to a "connection" or a "relationship" that exists, say, between trading partners. As to translations offered by non-English speakers, you don't really want to go there. It is hard enough to try to learn French but when someone is trying to put it into English and it is not their native language, it is usually wrong in ways that you could not even imagine.
Is "une" or another article always required when referring to "valeur"? It's just that in English, "value" is not a count noun.
"value" can be both countable and uncountable in English. For example,
He does not share his parents' values.
...I'm confused as to why we can't use "rapport". There's a reason it's a loanword.
Is the 't' in 'rapport' pronounced before a vowel (except 'et')? Always get confused since robochick hardly ever does pronounce it..