The word 但愿 is formed through a concise fusion of two independent concepts: 但, meaning "only" or "merely", and 愿, meaning "to wish" or "to hope". Their combination does not simply add their meanings, but instead creates a new, specific emotional stance. It encapsulates the idea of a singular, often earnest or humble, wish, a hope that is consciously recognized as perhaps the only one possible or the sole desire held in a given situation. Thus, the formation yields a term that conveys a focused and sometimes wistful sense of longing, distilling a complex feeling of "if only" or "one can only hope" into a single, resonant unit.