Passion. Romance. A charming young man who brings emotions alive.
With the Prince, we are entering into the stage where we fall in love. Trust is established, and there is a desire to move forward towards intimacy. Sometimes the prince can be unreliable; his heart can be fickle, trust your emotions. As with all court cards, the level of personal development can be crucial in working out how the card will manifest. In someone who is emotionally well developed, this card is likely to indicate the best possible expression and suggests someone who is artistic, visionary and creative. At the lowest end of the scale, he could still be charming, he'll say all the right things yet never deliver what he's promised.
The water signs of Cancer, Scorpio, and Pisces. Crowley gives from 21' Libra - 20' Scorpio. Look to see if there are other cup cards as this should help to narrow the sign down. The two or three would indicate more Cancerian energy whereas the six would be Scorpio. The Moon, The Hanged Man and the eight, nine and ten of cups would indicate Pisces.
Examples With Other Cards
Cups: with the Ace, Two, Three, Six, Nine, or Ten, it's more likely that this person is trustworthy and genuine. With the Seven or Eight of cups...I'd suggest being careful until some time has passed and a proper evaluation can be made.
Prince and Knight are interchangeable.