I got a male and female that looked very good together a while back. They were doing fine until one day the male just got mean and started nipping all the fins off the little girl. I thought it was a big disaster and took the female out to go to another tank. It turned out to be a blessing as within the next month, my tank crashed and the male mandarin (along with a wrasse, all my crabs except a ruby, all my shrimp except one peppermint) ate it. None of the corals, none of the snails, and none of the hermit crabs were harmed, so it turned out to be a freak occurrance and after 2 70% H2O changes, everything is back to normal. But the male beating up the female saved her life.
Sorry, went off on a little rant, but the point is this: no matter how docile the male is, they are very hard to pair and even harder to keep paired. The best way to pair these is to get a pair from the wild together. If you are still intent on pairing, be VERY cautious and do not automatically expect a good outcome. They are finicky animals with very little tolerance of others of its kind. Just a warning, take it for whatever its worth. Most online vendors will be able to get you a male if you are still interested...