Neither of those sentences is quite right, Laura, although we'd understand what you meant.

In modern everyday English, the verb 'fear' is mostly used to refer to a concern about something bad which might happen.

For example, if you use it as a transitive verb with a noun as its object, you can say that  you fear rejection, redundancy, illness or death.

You can also follow it with a phrase for example 'She feared that her husband would leave her' ( a fear about the future) or 'They feared that the boat had been lost in the storm' ( a fear about a possible event in the past). It's common in journalism to use this in the passive eg 'There has been an earthquake in xx. Hundreds are feared dead.'

Most other uses of the verb 'fear' are quite formal or outdated. I'd avoid using them, if I were you.

Grammatically, 'fear' is different from the other words.

In this context, 'fear' is a noun, not a verb*. You feel fear.  It is the name of the emotion, and it cannot be used as a verb in the same way as the other words. You can say It scares me or It frightens me or It terrifies me. These phrases all have similar meanings, and are in ascending order of strength. Scare and frighten suggest a similar level of fear, while terrify is much stronger.

You cannot say It fears me. 

With regard to meaning, 'horrify' has a different meaning from the other words. 'Horrify' does not mean 'scare'. If something horrifies you, it means that it shocks you a great deal. Synonyms for being 'horrified' are shocked, appalled, alarmed, disgusted. For example, you might say 'I was horrified by the high prices in Tokyo'. This is different from being scared.

*The verb 'to fear' exists, but it has a different meaning in modern English usage.