When it comes to describing the act of being fully committed to something or someone, "devote oneself" is a commonly used phrase. However, there are a number of synonyms which can be used instead. One option is to use "dedicate oneself," which conveys a similar meaning but with a slightly different connotation. Other possible synonyms include "commit oneself," "apply oneself," "pledge oneself," "immerse oneself," "engross oneself," or "throw oneself into." Each of these words or phrases can be used in slightly different contexts depending on the situation, but overall they all convey a sense of being fully devoted to something or someone.