Answer:
If you want to gain his trust back try admitting the mistakes you made and own up to them even if you don't want to. Also, being more responsible. Showing responsibility goes a long way trust me. Even though that won't gain his trust immediately it takes time so you just have to be patient as you gain his trust back slowly.
Step-by-step explanation:
Hope this helps:).......if not sorry for wasting your time and may God bless you:)