Grammarly

Grammarly’s sophisticated AI not only corrects your grammatical mistakes but also makes your writing more understandable and helps you make the right impression on the reader based on your audience and goals. In addition, Grammarly is able to check the tone of your correspondence, provide synonym suggestions to make your text more readable and precise, and even check your documents for plagiarism. With Grammarly, you can rest assured that your writing is always held to the highest standard. 

You can create a free account at https://www.grammarly.com/

Sample

Run spelling and grammar checks via Grammarly–Pay particular attention to Correctness.