The main objection to the Sagittarius - Capricorn relationship may be that there is little opportunity for them to notice each other in the first place. The signs typically have different styles and interests, and whether they are willing to stick around long enough to probe beneath the surface remains uncertain. The extrovert, intellectual personality of Sagittarius can make the reserved Capricorn curious, but they will remain skeptical of the naivety and carelessness of the Archer. Sagittarius is often impatient, and their first impression of the Cappy will be someone a bit too rigid or boring.
If they do get to know each other, their mutual sense of humor will unite them. Capricorn is known for their dry wit, and the Sag is often a master of satire and imitation. Nothing stops them from getting along fine, since both are quite rational at core. Deep emotional strain will probably not be an issue here. Sagittarius will come to be impressed by the quiet determination of Capricorn. The general outcome of the match depends on other factors in the horoscope: more to the point whether or not these will contribute with some passion and excitement.