An information heard from someone. Especially with high certainty. は 英語 (アメリカ) で何と言いますか？

質問を翻訳

According to Oxford's dictionary "rumor" and "hearsay" have the same meaning, and they are synonyms.
The only differences, which I noticed was the country of origin of these words, 'rumor' came from France, and 'hearsay' is an English word by itself.
So, there are no differences between 'rumor' and 'hearsay' in certainty.
And if you talk about unconfirmed information you may use 'rumor', 'hearsay' or more informal ones like 'gossips' or 'tattle'.
If you mean an information which is expected to be true, you may use 'report', 'evidence', 'message' or "somebody's words"
As think, in such situation it also can be used Complex subject structure (for example ("He is said to be fall in love" which means "[Everybody] says that he fell in love" or "it's a well-known fact that he fell in love".