There is a well known thing that most of the times dogs smell your fear and act accordingly. I was curious to find from the people who are well versed into horse caring, if it's the case here too. Does a horse sense you are scared to get up in it? Does the horse react in any way?

Horses are capable of sensing fear, they are very sensitive animals. A for how they react, it depends on the horses personality. Some horses will bear their teeth or flare their nostrils.

Horses are just the same as any animals would react. They would feel superior to you and might not follow you. My advice is to not let them know that you are scared of them, even it’s pretty obvious.

My horse right now notices fear in anyone and then feels fear herself. She is not a good horse for small children or people who have never been around horses. My last horse felt the vibes of people and if he sensed fear he would nudge your hand and make you feel alright. It all depends on the horse. I noticed that when ponies are raised around children and other pets they do better with fear and new people when they are grown.