Though we can see that you sent an email to your client, we're unable to check the content. Moving forward, it's best to set up a default email message. That way, you don't have to worry about what you have entered in the email as they'll have the same body of the email.
You can follow these steps:
Go to the Gear icon and select Account and settings.
From the Sales tab, select Messages.
Choose the Estimate from the Sales form drop-down.
Modify the message. You can also check the Email me a copy tick-box.
Hit Save and Done.
The Email me a copy tick-box will allow you to receive an exact the same email as what your client received. I have some articles here for more details about estimates: