If you check out the Swift tutorial tool (using the first switch for OpenEars alone), it will show you how to use the functions which give you the path to the generated language models:
Since lmPath is storing a returned string, it seems unlikely that lmPath.text is what you want. Another working example of obtaining this path in Swift can be seen in the Swift sample app that is in the OpenEars distribution folder.
If the issue is due to something else, it is necessary to turn on OpenEarsLogging and show all of the logging from the beginning to the end of the app run so I can help. It is possible that the language model generation isn’t working (it looks like this model is being generated out of a document, so I can imagine some complications there), so after the failed generation there is nothing to pass to the string, and the full logging output will indicate this if so.