Sentence examples for this one is from inspiring English sources

"this one is" is correct and can be used in written English.
It is usually used to refer to a specific item or person in a sentence. For example: - "Out of all the books on the shelf, this one is my favorite." - "I have tried many ice cream flavors, but this one is the best." - "I am considering buying a new phone, but this one is too expensive for me."