He never meant a syllable of it.
But Jeb can, in good conscience, break a pledge he made before the American people! He knew then that Trump, the leading candidate, was most likely nominee; that was the time for him to examine his conscience and refuse to take the pledge if he felt that he could not support Trump.
In other words, Jeb is an opportunist and a liar, who really has no conscience.
But then again, he has to live with the death of Terri Schiavo for which he and his brother are ultimately responsible. It is not surprising his so-called conscience is a ephemeral meaningless thing that can be flexed whenever it is expedient.
I think Jeb would do better not to talk about his conscience. It is abundantly clear he has none!