I'm starting to yous mutt + msmtp to send email with my gmail instead of Thunderdbird but i have a few question about encription:

I follow this tutorial for the configuration Using Mutt with Gmail and the resulting file was something like this:

account default              
host smtp.gmail.com          
port 587                     
from john.example@gmail.com     
tls on                       
tls_starttls on              
tls_trust_file /home/john/mail/certs/Thawte_Premium_Server_CA.pem
auth on                     
user john.example        
password rover          
logfile ~/.msmtp.log
The problem is that I get some problem with the cetificate file (not valid) and i had to change it in
and made a new conf file with

tsl check_cert off
My question is , am I still using the encryption in sending mail??? Where I can get a valid certificate ?? The mail is send encrypted just from my pc to the gmail server or till the destination server???