NUS Presidential Graduate Fellowship 相关事宜

本人在申请2021 Spring NUS的CS phd
已经联系好了导师，导师也很想要我，进行完面试，导师说想帮我申请 Presidential Graduate Fellowship，要求我手写一个
Letter of commitment to join NUS if you are offered the Presidential Graduate Fellowship:
-baidu 1point3acres           I, XXX, commit to taking up the Presidential Graduate Fellowship if offered by NUS.
我想问一下，这个承诺书是必须的么？ 我看意思就是如果我被授予了这Presidential Graduate Fellowship，必须去。。。（我有点犹豫。。）
有哪位大佬了解或者知道的，求问一下~~ 谢谢了