Is it possible to catch aids or HIV from french kissing? Is it unpredictable, sort or russian roulette?

No. Hiv is not found in high enough concentrations in saliva to cause infection, so kissing cannot transmit the virus, even if you both have chapped lips. If one person has active bleeding on the lips, then that is possible, but why would you kiss someone who's lip was bleeding? Truth is, there have been no known cases of HIV being transmitted from kissing.