I don’t know if I should trust him

So I met this guy months ago and we started talking and about 2 months later we still weren’t dating but it was like we were and he would always tell me that he loves me and he can trust me and etc but then I found out he was also talking to this other girl and he lied about it to me but he eventually told me the truth and he said he was sorry but he still wanted me so I decided to give him another chance and he says now he’s really serious about me cause the reason why he did that before was because he thought I would leave him and he couldn’t trust me cause the rest of his girls have done that so now he seems like he’s really serious and it seems pretty legit and we started talking hours on the phone but I still don’t know if I should trust him