Most honestly is a phrase used to describe a degree of sincerity and truthfulness. However, there are several other words and phrases that can be used interchangeably to describe this same quality. Some of these synonyms include "frankly", "candidly", "sincerely", "genuinely", "truthfully", "straightforwardly" and "with all sincerity". These words can be used in various contexts, but they all share the sentiment of being truthful in one's message. By using a synonym of most honestly, it's possible to vary your language and convey a similar meaning while avoiding repetition.