I am not sure if I should give him another chance

I trusted him, but he had a lot of secrets, as it turned out. The explanation was that he did not want to hurt me. He keeps saying he does not want to lose me, because I am important, but I am just pretty much unable to trust him now even if I keep trying. I don’t feel comfortable with always asking, neither with him being secretive or telling only part of the truth or coming up with excuses. I keep doubting him and also have told him, that he lost my trust and this would not even the second chance, but third or forth. I have told him to tell me one thing that makes me believe that this time it will be different. He has kept reassuring that this time he really wants it and he will try to do better, and show me the first time he has an opportunity to do so.