Antonyms for the phrase "with reservations" could include "wholeheartedly," "unreservedly," or "fully." These words suggest a complete and unwavering endorsement or acceptance of something, without any doubts or hesitations. Other antonyms might include "definitely," "completely," or "absolutely," all of which convey a sense of certainty and confidence. Alternatively, antonyms for "with reservations" might include "hesitatingly," "doubtfully," or "uncertainly," all of which suggest a lack of confidence or certainty in one's opinion or decision. Ultimately, the antonym for "with reservations" will depend on the context and the specific attitude or emotion being conveyed.