How do you trust

I'm staying single for a while because my last relationship has taken some time to get over but how do you trust again? Stop being insecure? I was starting to build trust with my ex then a few things happened and I found it hard to let myself trust him after those problems like literally when we were just dating I didn't have an issue but after a few things after we became official I had barely any trust left. So how can I trust someone again when I'm ready to date again? How can I stop being insecure?

Thank you all for your advice I'll take it all onboard 💛