The fact that love means many things, ranging from "Eros" (romantic love) to Agape (selfless love), suggests which quality of troublesome language?

Ambiguity.

Explanation:

To be ambiguous is to be unclear or inexact in what you are saying. In this context, the ambiguity comes with the need of both the speaker and the listener of saving effort when speaking. This impacts the language used, creating different types of troublesome language which, in this case, is the ambigous one.