There are several synonyms for the phrase "tries hard". One alternative is "exerts oneself", which suggests a great deal of effort put into a task. Another synonym is "strives", which conveys a sense of determination and persistence. "Endeavors" is another option, which denotes a strong desire to achieve a goal. "Works diligently" is also a suitable synonym, indicating a focused and conscientious approach. "Pushes oneself" and "labors intensively" are other synonyms that highlight the idea of putting in extra effort to achieve a desired outcome. Ultimately, these synonyms all imply a commitment to doing one's best and striving to succeed.