When looking for synonyms for "deeply comfortable," many words can come to mind depending on the context of the sentence. For example, one could use the word "cozy" to describe a homey feeling or the word "snug" when referring to a comfortable fit. Additionally, the words "relaxing," "cushy," and "comfy" all can convey a sense of comfort and ease. Words such as "serene," "peaceful," and "tranquil" can elicit a feeling of comfort from a relaxing environment or setting. Whatever word you choose, conveying a sense of comfort can help create a warm, inviting atmosphere.