The word 信心 is formed by combining two independent characters, each with its own core meaning, to create a new, unified concept. The first character, 信, carries the idea of trust, belief, or faithfulness. The second, 心, represents the heart or the mind, the center of thought and feeling. By fusing them, the concept moves beyond simple "trust" to express the specific state of having belief within one's heart or mind, it is the internal feeling or conviction of confidence, a steadfast belief held in one's core.