Verify the correct email

Help
,
1

I am trying to send the mail using gmail. I want to apply a check to email. How can we check if the email Id provided exists.
And also a check to password.

2

I think,
If you want to check whether the email ID is correct or not…
You must got approved for the google server…
That is the only way to check the gmail ID in Gmail server…

3

visit this