If you're not clear on your feelings for this person, you may end up confusing them in an unfair way, because they'll be quite emotionally attracted and attached to you from the start. They will recognize you at a deep, soul level, and they'll respond to you in that way -- thoughtlessly, simply throwing themselves into the relationship without waiting to find out who you are or what your stakes in the affair might be. Subconsciously, they're still enamored with someone they loved passionately in another lifetime, and that person may or may not have much to do with who you are today.
But if you're confused about your feelings for your lover or your stake in the relationship, you'll only make the emotional bond you share more confusing for you both. It's also possible that you'll each deceive one another, whether on purpose or by accident. Honesty will be a slippery and elusive pursuit between you, and therein lies the karmic lesson of this relationship. If you can be completely open and aboveboard with this person, holding nothing back and refusing to mislead them as to your intentions, then you'll be able to resolve your own part of this difficult karma that you share.