Hitting a really rough patch with my GF of 5 years.

Hello everyone, just going through a very rough patch with my gf of five years. It’s something that I have come to realize that we both need to communicate better and work on things together to get our relationship in better shape. Throughout the years it was been great and had some rocky moments like any relationship would have gone through. Recently we’ve just been getting better after a small blow out and had a misunderstanding and I did not mean to overstep her boundary and made her felt like she did not feel safe and secure in our relationship but I have acknowledged what she has said and apologized and told her it wouldn’t happen again but she doesn’t take my words in face value and it becomes frustrating. I am currently just giving her space for some time now but can’t help but think about what needs to be done properly to work things out without being dismissed and patch things up together. Thanks.