There was never any basis for thinking he was telling the truth. Through most of his public life, Trump was militantly pro-choice. While people can change their minds, there is no evidence that Trump did. When Chris Matthews asked Trump about his evolution on abortion, it was immediately evident that Trump had not given the issue so much as five minutes of thought. Over the next six hours, he adopted four different positions on abortion. 
Trump has said that he will nominate "pro-life" justices to the Supreme Court. However, the prism through which he'll nominate is not abortion -- he'll be looking for judges who are sympathetic to his business interests and who will not oppose him as he privatizes the presidency. Some may vote to overturn Roe, but that would be only a coincidence; and it won't prevent one abortion.