How do you re-gain trust in someone?

My boyfriend of 1 year and 7 months have had our ups and down like every couple. But, a few months back he did something to compromise my trust and we nearly broke up. He hid and tried to lie about something quite big. (this didn’t involve a girl just btw)

After a long night of me just going off on him and both of us crying. I decided to give him 1 more chance. I told him I will not be mistreated again. He apologized for everything and told me he’d gain my trust back.

My trust in him has somewhat returned, but not like it was. He hasn’t lied about anything, that I know of since then. We’ve gotten into little arguments, but it all usually got resolved by the end of the day.

How do I try to trust him fully again? Will I ever?

Anyone been in a similar situation? Advice definitely needed.

Please be nice lol.