The creature hiding from you has reasons that your harmless intentions cannot explain away.

Intentions are known only from the inside. The animal backing away is not making a judgement about you personally; it is working from a long history of encounters with things your size, and nothing you feel about yourself is available to it. The same applies with people who flinch from something you meant kindly. Their caution was built before you arrived and is not an accusation.

When someone or something keeps its distance, let it. Move slower, stay predictable, and let time rather than reassurance do the work. Being trusted is granted by the other party, never established by your own certainty.