Don't really know as I haven't tried it. But this would seem a very simple thing to test for yourself by setting up a simple layout with the details you want to test and then using FM GO to save and emailing the PDF to yourself to see if it works.
If you run such a test please report back here for the benefit of others. (I think it will work myself...)
I have tested Filemaker Go 13 using a layout with a merge field spanning across 2 pages within the body of the layout. "Allow part to break across page boundaries" is selected for the body part. I have the layout saved as a pdf report. The pdf report has not successfully divided the text between the 2 pages i.e. the last line on first page has the bottom of the text sliced off which appears on top of the second page.
Has anyone got any other suggestion?
You may be able to make small adjustments to your layout until the page break falls cleanly between the lines of text in your field. This will be tedious to do however since you can't check the results in preview mode like you can in FileMaker. (Some versions of FileMaker have the same issue.)
Another option that can sometimes be used is to figure out a way to break up the text in this field into smaller units that can each be placed in the text field of a set of related records, Then you print from a list view layout based on this related table. You can then, sometimes, choose to not let the body break across a page break and get an acceptable result.