There are seven speech levels in Korean. (https://en.wikipedia.org/wiki/Korean_speech_levels) As like other conjugatiosn, the imperative conjugation also exists for each levels. 1 Higher levels 1.1 Hasoseo-che : -(으)소서 1.2 Hasipsio-che : -(으)ㅂ시오 2 Middle levels 2.1 Haeyo-che : -어/아요 2.2 Hao-che : -(으)오 2.3 Hage-che : -게 3 Lower levels 3.1 Haera-che : -어/아라 3.2 Hae-che : -어/아 For example with 가다 Hasoseo-che : 가소서 Hasipsio-che : 갑시오 Haeyo-che : 가요(attached with 시 -> 가세요, 가셔요) Hao-che : 가오(attached with 시 -> 가시오) Hage-che : 가게(attached with 시 -> 가시게) Haera-che : 가라 Hae-che : 가 The followings are all correct with different speech levels. 무서워하지 마라. => Haera-che 무서워하지 마세요. => Haeyo-che with honorific partice -시 무서워하지 마. => Hae-che

-마라 seems to be imperative. (depening on the situation) -마세요 seems to be polite and could be used to strangers. For example, you are walking a dog and a stranger is coming on the opposite side. In that case, you can tell him or her that 무서워하지 마세요. -지마 seems to be friendly and could be used to friends or people who are close.