Miss someone and want to let them know

I miss my friend and ex girl friend I reached out and sent her a simple message on Instagram she responded by just hearting my message. I wanted to reach out to her since this day but I also am trying to be respectful, spending a lot of time focusing on thing a I want to be doing and that's just it I had a friend pass away this year and truth is I want to let this girl know how I feel about her. We had minor issues along the way just like any relationship but a the truth is I don't want to lose her in my life and the thought of that scares me feel free to roast me but advice would be greatly appreciated