Sentence examples for it's been so from inspiring English sources

"it's been so" is correct and usable in written English
It is typically used to express that something has been a certain way or has happened in a particular manner. Example: "I can't believe it's been so long since we last saw each other." (This means that a lot of time has passed since the last time the speaker and the other person saw each other.) Another example: "It's been so hot this summer." (This means that the weather has been consistently hot throughout the summer.) "It's been so" can also be used to emphasize a strong emotion, as in: "I'm so grateful it's been so easy to work with you." (This means that the speaker is very thankful for how easy it has been to work with the other person.)