Hello Chen Ke Chi,
University of Massachusetts Amherst has 5% of international students.It is always difficult to get into a US university as an international student, especially when you require financial aid. And University of Massachusetts Amherst doesn’t provide need based aids to international students.

Yeah, I agree with the previous answer. Try searching for sponsorships in your country as well. The university provides merit based scholarships too but I am not sure if international students are eligible for them. Better look their profile in OYA School or search in their website or maybe ask them.