I do comment this thread for saving time for users of this product.
My history - convert a banch of documents based on Word to jrxml (about 200 different documents).
As i found, in this time there is no straight converter helping to simplify this routine.
My expirience.
Save Word document as HTML (with filter to avoid MS specific tags of markup).
File prepared on step 1 open in Notepad++(i used this) - Find and Replace in extended mode \r\n on ' '(whitespace).
File prepared on step 1 open in Notepad++ - in this file - Find and Replace
in regexp mode <p[^>]*> on <p>, also Find and Replace in regexp mode <span[^>]*> on <span> (better to record macros on that actions).
After these steps you get cleaned source ready for TextField with html markup.
Last action - use gotten markup in step 4 for placing in text field(s) with html-markup property enabled.
P.S: tables will be lost on converting bcs JasperStudio does not convert these tags, i used TextFields with enabled borders.