I think you mean an incomplete expression of "this is really very" by 이것은 참 아주!". If I am right in my understanding, my answer is "yes". We often use this kind of incomplete phrases, particularly in an exclamatory sentence.

Yes, you can, but it's not the standard.^^/ Here are other variants. 참아주! - sounds cuter ^^/ (= 참아줘! or 참아주세요!) 참아주라!(= 참아줘라!) 참아주삼!(= 참아줘!) All are often used for texting or the internet chatting. \^o^/