assiduously, avow, gallivant, monopolize, steadfastly
Despite having been seen gallivanting around with Vanessa Minnillo, Nick Lachey avows that he is steadfastly single. He maintains that he has been assiduously focused on his career, which has monopolized all of his time.
gallivant - (verb) to go around with in an obviously flirtatious manner (usually with a member of the opposite sex); to roam around looking for amusement
avow - (verb) to state as true; to admit openly and without shame
steadfastly - (adverb) firmly; steadily
assiduously - (adverb) constantly and carefully (with respect to attention or activity); persistently
monopolize - (verb) to control completely; to dominate