Hiding the original FROM sender address when using "Send As"?

Question

When sending from Gmail's web app on an account configured to send mail from another email account (in my case, another Gmail address), is there no way to conceal the original account's email address?

There are a lot of similar questions here, but either they relate to using a private domain with Google Apps, or I've already tried the solution proposed, which is switching the aliased account to a non-Gmail address (Outlook.com) and sending emails directly via the non-Gmail (here, Outlook's) secure SMTP servers. Nevertheless, recipients still see On Behalf Of in my emails. I can post some cleaned up headers if helpful. (here's what I've tried; How do I get rid of on behalf of from my sent Gmail messages, How Can I Remove On Behalf of in Gmail , support.google.com/mail/answer/22370?hl=en&ctx=mail )

I don't have my own domain to authenticate my email against; I assumed that using the Outlook SMTP servers would suffice.

I'm sure there are good authentication and spam-related reasons for all this, but since I have control over both accounts, I can't see the reason for inserting this info. Do I really have to keep a separate private window open, or switch to a proper desktop client? And what to do for mobile?

FWIW, I tried this same experiment with an Outlook.com email account (configured with Send As aliases), and not only do the native Microsoft aliases show up correctly in the recipient's email, but so do non-Microsoft aliases (meaning, while logged into Outlook.com's web app, I can send my email as FROM a Gmail account, and the recipient will see it as such).

I prefer Gmail's interface (filtering, keyboard shortcuts, etc), but this is enough to make me switch to an Outlook account (whose interface seems to have improved a lot since I last used it.)

Answer 1

The problem with the threads provided in the question is that they are outdated. Gmail currently does not allow you to access your other gmail account through SMTP. See https://support.google.com/mail/answer/22370?hl=en

What you can do though, is to get any other email account being not provided by gmail, but having an SMTP access. Then add it via SMTP, which basically makes your gmail inbox a web-based client for those accounts, so the email address of that inbox will not appear anywhere in the message.

Answer 2

In GMail settings select "Accounts and Imports" (In english may vary, i have spanish lang), and in section "Send messages as" select "Add another email account" and when asked, DON'T ADD IT AS ALIAS!

Why?

Because if you add it as an alias, Google Mail Servers will appear as senders. If you add manually the other server (Original Account) GMail will act just as an handler (Like Microsoft Outlook App).

If you want to receive the other account mail, add it into "Check other mail account (POP3)". Will import all INBOX mails.