How can he gain my trust back?

Alright, so me and my boyfriend have been together for a good amount of time. We love eachother and always tell eachother the truth even when it hurts. But we recently havent been able to see eachother, it’s been about a month since I’ve been with him, and we had a chance to see eachother but he told me he had to go to the supermarket. but he actually went to go fight some guy. He wanted to fight him for a while. So he went to fight him, and went back to his house, called me and we talked for a while, then he randomly told me towards the end of the conversation. He said he was apologizing because if he didnt ho thought something bad would happen, he believes in a good deed bad deed kinda thing, so basically if he didnt tell the truth then something terrible would happen. But I think that his apologe wasnt sincere. I want to trust him, but it makes me sad that he lied, and that he knows I hate fighting and still went, he feels terrible and wants to gain my trust back, what are some good starting ways to build it back up? I’ve told him not to lie to me anymore, but he wants other ways. He really is a great guy, and I know he wants to make things right.