If someone is giving mixed signals, it's usually time to have a conversation. Expressing a romantic interest or asking to clarify their intentions will answer the real question: is this something I want to pursue? If the person is unable to give you a clear answer about how they feel and express that they are ready to choose this connection, it doesn't really matter whether it's due to a lack of feelings or a lack of healing! They are unable to choose you in either case.
Having the conversation:
Express that you're asking to understand and make the best decision for you, not to pressure them in any way.
If there are feelings on their end but they express hesitation in moving towards commitment, you can gently ask 'what fears do you have about getting into a relationship?' More information will help you discern whether they would be willing to overcome those fears with reassurance from you and gives you an opportunity to share relevant info about your view of relationships (e.g what a healthy relationship can look like)
Be honest about what you want
Believe what they say. If they say aren't ready for a relationship, they aren't ready. Don't stick around trying to earn their love or settling for a casual connection when you really want a monogamous relationship. Choose yourself always.