Should I believe my long term boyfriend about our future

I have been with my boyfriend for over 4 years now. he is an amazing guy and we have a great relationship. We are both in our late 20's. When we first started dating he said that he wanted a family. Later in our relationship when I brought up the idea of children he said that he didn't see himself with kids right now. I'm not sure why he said that but it got me thinking. I want to be a mother at some point. Not right away but within a few years. So thinking that he never wanted kids and that was a deal breaker for me, I decided to leave him. It was the hardest decision. I was breaking his heart and mine. I felt I needed a man who shares the same values as me. So we have been separated a few months with no contact. It has been hell for me. He was my best friend and I feel like there is this whole I'm my heart that can't be filled. Then one day he texts me saying that he would like to talk. So I decided to hear him out. He told me that he loves me and misses me dearly. And I told him that I left him because we wanted different things in life. He then started to get emotional and he said that he wants to be the best man that he can be for me. He said that he didn't want kids at the moment because he's scared. Scared of failing at being a dad. He said that he isn't against the idea of having children. I wondered why he couldn't say this before? I could see it in his eyes that he truly meant what he said. My concern though is that he is saying this out of fear, fear of losing me and then when we get comfortable again he will fall back to where he was. You can't run away from the things you're scared of. Life is really scary. He says he wants to take our relationship forward and commit to me. I love him more than anything and want to be with him. I just want to know that he really wants this and is not just saying it impulsively. He is saying not right now but he isn't saying never. I just am worried that he may never be ready. I'm not ready either at the moment but I know I will be at some point and I'm not sure if he can say the same. I told him I don't even know if I can even have children and he replied with, all we can do is try. Having children isn't something you rush into but do I stay and hope he will be ready at some point?

I would take him at his word right now, he obviously loves you and wants to be who you need him to be to further a relationship with you...the idea of having kids scare women too. Do you have a timeline on when you actually want kids? You want to get engaged and married first? Then have kids, or that isn't important. Maybe both talk about your own timelines on this subject.