The term "desirable growth rate of income" can be expressed in various ways to convey the same message. It could be referred to as a "favorable income growth rate," "optimal income increase rate," or "sustainable income growth rate." Other synonyms include "acceptable income expansion rate," "positive income growth target," and "promising income gain rate." These expressions all communicate the importance of a steady and foreseeable increase in income over time, which is crucial for personal financial growth and stability. Thus, by using these synonyms, one can convey the same meaning as the original phrase while adding a touch of variety and specificity to their writing or conversation.