There are numerous synonyms for the phrase "be with one," which essentially means to accompany, support, or stay by someone's side. Some synonyms include "stand by," "back up," "assist," "help out," "be by one's side," "stick around," "stay close," and "be present." These phrases are commonly used to describe someone who provides emotional or physical comfort to another person during a time of need. The phrase "be with one" can also refer to a more romantic relationship, indicating a desire to spend time and be deeply connected to another person. Overall, the phrase is used to convey a sense of loyalty, commitment, and caring in various types of relationships.