I often send an email using Gmail to someone (say A) who does not use Gmail. Often, I use Gmail's formatting buttons to make some text italicised. Often A's reply includes parts of my message. In those parts, my italicised text is always coded as asterisks, e.g., a.abcd from my original message is shown as *a*.*abcd* in the reply in my Gmail.
This seems wrong to me. Ideally, I should see what I wrote. More importantly, now I am worried about how their mail client showed them my message. If it showed the text as *a*.*abcd*, I could be in great trouble, because that text may represent something like a username, and unless A mentally decodes the asterisks into italicised text, he/she will misinterpret my message.
How do I find out where things went "wrong"? I noticed that Gmail sends my message as both plaintext and HTML. In the plaintext version, italicized text is coded using asterisks. Also, the HTML version comes after the plaintext version in what Gmail sends, thus indicating to the receiving client that the HTML version is preferable. The reply is only in plaintext format.
Can I do something to be sure that my italicised text is always interpreted correctly?