How do I get my mother to trust me?

Hi so I am in need of some advice, I'm 16, right now I'm being constantly harassed by my mother-.-
like seriously she doesn't trust my boyfriend meanwhile
it's been a long time time since I've been dating him and
I love him.sure I've been lying telling her that
we've only met just a month ago but what
assures her not to trust MY boyfriend I am urged to tell her a thing or two since she divorced
my dad after being with him all her life.
I feel like she's just trying to ruin it for me since
her love life is ruined. Any advice pls I'm desperate ╯︿╰