I think that would be "bisi azantyssy syyri issi"

Because that ks a question, and the above sentence does not end with a question mark. To ask a question in High Valyrian, you just say the statement with the intonantion of a question. In theory, the above sentence couod mean "are these good knights", but due to the intonation of the speaker and the lack of a question mark, it isn't.