In fear and trembling can be substituted with a variety of similar phrases that convey a sense of anxiety and apprehension. Such synonyms might include nervously, hesitantly, with trepidation, or with bated breath. Other options could be in a state of panic, fearfully, or with a pounding heart. Additionally, some might use phrases like with a sense of foreboding, with a feeling of unease, or with a deep-seated sense of dread. Ultimately, the particular synonym chosen depends on the context of the sentence and the specific shade of meaning that the writer or speaker wishes to convey.