Let's use the Unlimited Email Tracker extension. With the help of it, you will find out whether your interlocutor has read the message or not, and see how many times it has been opened.
The extension also shows the number of clicks on the link in the letter, postpones messages and notifies you every time you open the letter.
In order to use, you need:
1. Install the extension 'Click Here'.
2. Activate it for your email.
Ready! The extension is free and unlimited. Available for Chrome and multiple Gmail accounts.