There are many ways to express the idea of happiness in various contexts. Some synonyms for the phrase "with happiness" might include "joyfully," "with glee," "blissfully," "ecstatically," or "elatedly." Each of these phrases conveys a slightly different shade of meaning, with "joyfully" suggesting a lighthearted sense of pleasure, "with glee" emphasizing a more exuberant or playful mood, and "blissfully" implying a deep and profound sense of contentment. Similarly, "ecstatically" and "elatedly" both indicate an intense and joyful emotional state, but with slightly different connotations. Ultimately, the choice of synonym will depend on the particular mood or tone the writer or speaker wishes to convey.