SEDULOUS

diligent

persistent

hard-working

marked by care and persistent effort
SYN - assiduous
"sedulous pursuit of legal and moral principles"

"He was sedulous in his attempt to get into grad school, which he was hoping would show real results."

"She scoffed at the speech given praising his sedulous work towards helping the lower class."

"He only had respect for people who knew what it was to have a job that required you to be sedulous."