I'd wager something like,
"In a safe and positive manner, my aura is attracting my ideal, perfect soul mate to me. This person is romantically available and compatible with me in every way."
...modified slightly to suit your needs as you deem appropriate. The main thing is to affirm that they're available and compatible, with something extra to affirm that you are beginning a relationship with this person if you feel the need to ensure that. I'd imagine that if they're your ideal soul mate and they're available, it might not be necessary to affirm that you're entering a relationship with said soul mate, but I leave that to you to decide.
Venus retrograde will definitely render this working unviable, so you ought to wait until it's direct. I'm not too familiar how Venus' sign impacts love workings, but beside Taurus and Libra, Cancer seems like it'd be an acceptable sign for a love working.