The phrase "has doubts" can be expressed in a variety of ways using different synonyms. These include "uncertain," "unsure," "hesitant," "skeptical," "questioning," "dubious," "indecisive," "ambivalent," and "apprehensive." Depending on the context, some synonyms may be more appropriate than others. For example, "uncertain" and "unsure" are often used interchangeably to refer to a lack of conviction, while "skeptical" connotes a healthy dose of skepticism or suspicion. Ultimately, the choice of synonym should reflect the nuance and tone of the situation at hand, as well as the writer or speaker's intended message.