You know, I never could figure this out either - concerning Ziyal or his other children, for that matter. Dukat was such an...an actor, really. (And yes, I am talking about Dukat, not Marc Alaimo.
) He was, or so it seemed to me, always playing to an audience, and often it seemed to me that the audience was himself. He saw himself as this heroic figure, that's the role he played, and he played it to the hilt.
So was his love for his children genuine? Or was it part of the act? Or was it both?
I'd guess the latter. Surely there was some real love there - I mean, he did pay a high price for acknowledging her. But with somebody as addicted to being loved and admired, to being seen as the hero, as Dukat was, I can't think it was pure love. Ziyal would be a wonderful source for his drug of choice.
And really, how many of us, myself included, are capable, day after day and year after year, of 100 percent pure love anyway? I mean, nearly everybody is capable of this at certain times, and really wonderful people (which Dukat, of course, was not) are capable of it often, but all the time? Probably not. Love is a strong instinct but so is self interest, after all.