How can i earn my boyfriends trust back when he no longer trust me?

Just try to speak to him. Tell him u know u did wrong and try to forgive me and I will never do it again.

If you have done something grave to betray his trust.Its difficult to get that back.

He might have problems trusting you enough to take the first step.You have got to make him believe that you don't have malevolent intentions in mind.And if there is something simple that you know he wants you to do, do it.You don't have to demean yourself for that.Do it in a way that gains his respect and trust.

Cheers