Do I believe him? No. Why should I?
Trump had actually toyed with the idea of running against wee barry, in 2012, but never did pull the trigger! And prior to that, he had mentioned it, here and there, for years before that.
By 2015, he just got totally fed up and did this on his own.
Should you believe him? That's totally up to you, makes no difference to me.
You are demanding perfection of explanation before you will deign to consider information worthy of your acceptance; that is an impossible standard, but I think deep down you know that.
The very fact that you don't believe in children as the currency du jour of the global elites is simply staggering. It is common knowledge and anyone with an ounce of intellectual curiosity knows this. Quit being so complacent and do some research, at the very least you will expand your horizons.