Capricorn acts within the limits, while Moon in Sagittarius needs to explore beyond the limits. Capricorn may feel dull and controlling to Sag–the more he tries to impress her with his authority, the less interested she’ll be. However, both these signs want progress, so this could be a commonality that ties them together.
Mars in Capricorn follows the rules. He’s ambitious and driven, but you won’t find him breaking with tradition. His classic and conservative approach to courtship means that his lover can rely on him. Mars in Capricorn won’t do anything crazy, and he always follows through on his intentions. His ideal partner would be ok with him taking the reins of the relationship, because he asserts himself by taking control.
Moon in Sagittarius needs room to follow whatever takes her fancy. In her heart, she’s a wanderer, even if she’s in a committed relationship. Moon in Sag does best with a lover who accepts her laid-back approach to life. She feels passionately, but her optimism and humor can come off as uncaring at times, when she doesn’t take things seriously. She refuses to get caught up in worries or dark feelings. She feels most secure when there’s something new to discover, preferably with her partner. But if her partner’s not interested, she’s just as happy to go exploring on her own.
Mars in Capricorn’s best efforts will fail to impress Sagittarius. She’ll find him amusing, but she won’t care about the goals (like status and achievement) that drive him. If other aspects between their charts suggest chemistry, they might try to make a go of it. But there will always be tension between Capricorn’s efforts to maintain his authority and Sag’s complete disregard for his authority (and much of what he takes seriously). However, Capricorn’s ambition and Sagittarius’ need for expansion can be a point of compatibility, if they develop tolerance for each other’s differences. Capricorn can help Sagittarius manifest some of her hopes, putting in the practical work to make them happen. And Sagittarius can use her unfailing optimism to support him if he becomes discouraged.