For many years on Windows, I always check my Gmail boxes out via Chrome browser and that's a boring task.
I need an email client that be safe and best for a home Windows user. (I’m not a security expert and don’t know about email and transferring security, so I don’t know how to say and explain it from a technical view. But I don’t like my emails hack and accessible by hackers or check them out by my ISP or see and stole by companies and receive spams or whatever annoying things with it)
Also, I have six email addresses, and I expect an email client support all emails at once to see all boxes without switching among them or need to close one and open another.
UI is almost important for me, but the most thing I care about it is security.
I'm thinking about "Thunderbird". What do you think about it? Is it safe and good for me? and if it fulfills my needs (security, UI, and support to add six email addresses and checked them all at once?).