There are some threads on API and Email 2.0.
Marketo will not store the Breaks and Bold text in a text area field or even any field. the email does not look nice.
That's not really an accurate way of putting it. Marketo fields can absolutely store HTML, and this isn't a Marketo issue.
When you you use a standard <textarea>, no HTML markup is generated (line breaks in textareas are true ASCII 10 linefeeds, not HTML <br> elements). You must use an editor like TinyMCE or ckEditor to enhance the <textarea> to allow formatted text and store it as HTML.