It is one way of checking, but it can be a whole range of things that make you suspicious.
Suppose you got a genuine email from say Tesco the "text" may say "Tesco email" or similar but if you "hover" the address it goes to may be a genuine Tesco email address, so it that case they are different, but it is OK.
The problems comes, for example, if the "text" says "Barclays Bank" but the "hover" words say "www.splayxyz.ru/login" then you might be worried.
It does pay to look at the country of the web site. So above you see it says "splayxyz.RU". Well RU is Russia and Barclays are not going to send a email from Russia (or Turkey or China and so on).
So check if it is "UK" or "COM" at the end and if it is any other country beware (though you cant be certain the UK or COM are genuine either).
ALWAYS be careful if anyone asks you to verify your account by logging on to a web site to "very" your account. This is almost certainly spam (called phishing") and all they want to do is steal your userid and password.
Even if they say you are going to lose your account if you dont verify it, dont believe them.
Also beware if it is from somone who does not have your email address, say the Income Tax people, where you get "dodgy" emails saying you are due a tax rebate when you have never given them you email address.
So it is no one thing, but a collection of things that can lead to you thinking it is spam or junk or phishing email.
If in doubt DONT reply to any email.