재료 = raw material; base material; ingredient. 성분 = constituent substance or material; component. 재료 emphasizes the raw state before being used or processed. (음식의 재료) 성분 implies that the constituent component is not easily recognizable, as in drugs and chemicals. (화합물의 성분 = constituents of a compound material). For 참사랑, I doubt either word is appropriate. There is 요소 (essential element/component/ingredient) which I thinks is better. 구성 요소 (key components), 기본 요소(basic components) are also common phrases. So you might say "참사랑의 기본 요소" (basic components of a true love) or "참사랑에 꼭 필요한 것" (things that are really necessary for a true love). Note that 재료, 성분, 요소 are all relatively formal words not used much for social relations (except in some serious writings). 참사랑에 (꼭) 필요한 것 or 참사랑에 중요한 것 (what is important for a true love) or 참사람에 요구되는 것 (what is required for a true love) is what most people would say.