Sentence examples for will be completely from inspiring English sources

"will be completely" is a grammatically correct phrase and can be used in written English
It is typically used to describe a future state or action that will be fully or entirely completed. Example: "The construction of the new building will be completely finished by next month." (This means that by next month, the construction will have reached its final stage and will be fully completed.) Another example: "I will be completely focused on my studies this semester." (This means that for the entire semester, one's focus will be entirely on their studies.)