Michael Smith's answer is correct. You should use "Mrs." (pronounced "misses") for a married woman, and "Miss" for an unmarried woman. If you don't know whether she is married or not, you use "Ms." (pronounced "miz"). Some women prefer to go by "Ms." rather than using the married or unmarried forms, but they'll usually let you know if this is what they prefer. You can also just ask your teacher what she prefers. Some teachers (including university professors) ask their students to simply use their first names.

Dear Meryanta, In answer to your question, I believe it is customary to address orally said teacher as "Miss". Her full name however will be Mrs. Sembiring (pronounce /misiz/). You may use it in writing or when referring to her in a conversation with someone else. Cordially. Thomas

Mrs. Sembiring. Pronounce it "misses"