Yes, Bluestacks is completely safe to use. I had also used it.
Bluestacks is basically a Android Emulator for PC which enables the Windows OS user to run Android apps on his Windows OS system.
Bluestacks is an American technology company that produces the BlueStacks App Player and other cloud-based cross-platform products. The BlueStacks App Player is designed to enable Android applications to run on PCs running Microsoft Windows. The company was founded in 2009 by Jay Vaishnav, Suman Saraf, and Rosen Sharma, former CTO at McAfee and a board member of Cloud.com.
To download Bluestacks you visit here : https://www.bluestacks.com/download.html