Judging teaching is like diagnosing measles.

There are many things that can indicate measles, but no single indicator is proof of measles. A few spots doesn’t mean you have measles because there are plenty of other reasons why you might have spots. However, if you have spots and a temperature, and if the spots persist for longer than hives or insect bites, then you can be more confident of the diagnosis of measles.

Likewise, good scores on one evaluation questionnaire doesn’t mean you are a good teacher, because there are plenty of other reasons why students might have given good evaluation scores, and we don’t know whether the evaluations are equally good in your other courses (and neither does one bad questionnaire mean you are a bad teacher). However, if a teacher gets consistently good results from evaluation questionnaires from multiple courses, and over multiple years, and their peers also say they are a good teacher, and their students do well in their assessments, and in later careers, then you can be more confident that they are indeed a good teacher.