確かだ
That news is certain.
その知らせは確かです
That news is quite certain.
その知らせはとても確かです
That news is quite certain because it was announced.
その知らせは発表したので、とても確かです
That news is quite certain because it was officially announced.
その知らせは正式に発表したので、とても確かです
That news is quite certain because it was officially announced yesterday.
その知らせは昨日正式に発表したので、とても確かです