How do you trust someone again?

if you love her and want to give her a second chance you wont be able to go back fully into it without feeling different. you will have to have a long talk with her, and explain to her that she is going to have to gain your trust back. it may be awhile before it feels like it used to. dont fight with the past with her and try to move on, dont bring things up that are only gonna start fights. if she is willing to try to do this for you and wants you to regain her trust it should work out but do not go into this blindsided and make sure you are open and honest with each other about everything.