YOU SAID:

sienna struggles with school but is able to be the smartest person in my class

INTO JAPANESE

シエナは学校で苦労していますが、クラスで一番賢い人になれます

BACK INTO ENGLISH

Sienna has a hard time at school, but manages to be the smartest person in her class

INTO JAPANESE

シエナは学校では苦労していますが、なんとかクラスで一番賢い人になっています

BACK INTO ENGLISH

Sienna has a hard time at school, but manages to be the smartest person in her class