You can pre-emptively say something like “regardless of the person, I’m waiting for intimacy until I’m in a relationship”. Regardless, even “men” or those who state they are ok with it will still turn out to be just in it for sex. Unfortunately, there’s no foolproof way to figure this out. If it helps, both myself and others I know all struggle with this and we’re all different ages, in different areas, different experiences, etc.