You should ideally be using alternative words for belonging and not belonging in your essays/speech written in the area of study-belonging, the reason being by using alternative vocabulary-you are showing the marker you understand the versatility of belonging-in that it can be the expression of individuality, the cultivation of a sense of communal solidarity, it can involve cultural estrangement/diaspora, social seclusion/alienation and etc... try to replace the synonyms with the words 'belonging' or 'not belonging'- and you will see a big difference in the variety and complexity of your expression of your ideas. You should check with your teachers to see whether she will prefer the use of alternative words, but in the long run, for any future modules, try to avoid the overuse of a particular word associated with that module in any essay or assessment task you do.