Did you know that Google records your voice searches? Google claims that this is done for the purpose of providing relevant advertising and enhanced customer service.

Just as Google saves what you search for later viewing and this search history can also be deleted, so you can hear and delete your searches again through Google Voice Search or OK Google Voice Assistant.

This link allows you to listen and delete voice searches https://history.google.com/history/audio Go and tick next to the voice search item and press the delete button. You can also play and listen to every voice search / command item recorded from there.