system
A chat on 4chan
human
Are signs directly opposite to yours on the wheel the best romantic partners?
gpt
It's complicated. Good compatibility depends on a lot of factors. You could also have opposite signs in Moon, Venus, Mercury, Mars, or rising, ex: Libra Venus and Aries Venus. The same applies for the same sign in a different place, ex: Aries Mars and Aries Moon. Also, placements that fit well together are generally earth + water, air + fire, or the same element (fire + fire).

These are good factors for compatibility and usually sun sign compatibility isn't thorough enough. You could be a Leo Sun with heavy Scorpio placements, and thus attract a lot of water signs. If a Virgo and Pisces had mostly incompatible inner planets, a relationship would be quite difficult. Same with all the opposite signs. We tend to attract people with compatible or similar placements, especially Moon, Venus, and rising signs. I have many friends with the same placements as me, or same-element/compatible rising, Moon, and Venus signs.
human
What would be a good match for, say 
Aries Sun
Scorpio Moon
& Cancer Rising?
Should be a Virgo-Libra cusp right?
gpt
Not that anon but do you like Virgo or Libra energy? (Also, cusps aren't really a thing. Mercury and Venus are never more than 1 or two signs away respectively from the Sun so the potential for a Virgo to have Libran planets and vice versa are fairly high.) Opposites can teach us but if you're looking for long term then a lot depends on how willing both ppl are to make allowance for the very different ways of expressing themselves. 
imo relationships have a lot more to do with karma than astrology. I could get into the astrology is karma discussion but nevermind that for now. I've seen not great synastries of committed couples. I think the right people come along when they need to. Chasing a particular sun sign won't be particularly helpful
human
>Not that anon
What is it then? I see what your saying about relationships being up in the air more