Try to find common ground
When two "truths" are in conflict, it is helpful first to seek that on which we can agree. So asking questions to understand the other's "point of departure". Before speaking of bad faith, you must be sure that there's not simply a misunderstanding or an error of judgement.
A simple and very useful rule: concede to the other the assumption of good intentions and signal this clearly to him ("you want things to move forward as much as I do...") Even if he is concealing information, this is not necessarily in order to do us harm, or from blatant dishonesty.
Announce how we will adapt
If you do not, through dialogue, find common ground, then persevering will be counter-productive. More effective:
1- identify how you will act to lessen (or eliminate) the consequences the other's behavior has for you
2- announce it calmly, like you would declare a logical decision.
We do not seek to change the other but to change something on our part which will, perhaps, cause the situation to evolve.