I agree with everyone else. I have been using grammarly for almost 2 years and I never had a problem with viruses or anything. It is a good product and well worth the investment.

Yes, it is totally safe for adults and for students attending school.

Grammarly is very safe to use.
I've had no issues with Grammarly ever in my life.
In fact, I am using Grammarly right now!

Did somebody ask himself what is earning model of Grammarly?
To be able to correct or optimize your text... you need to give free your valuable text. Is it a business deal, is it a research document, is it about customer data, is it about strategic information? I would not do that... prefer to have some mistakes in such documents than a much bigger mistake which is giving my data for free.
No way!

As far as viruses etc. I've had no issues. Grammarly Support is a nightmare (there is no support) and for editing a manuscript it's useless. I think for basic grammar okay but even then mistakes occur. Good luck!

I have used for several years. If you mean by "safe" an issue with viruses, tracking of users or malware, I have seen no such issues. I do check my computer regularly for these.