(used of persons) dependable in devotion or allegiance or affection; "a faithful old dog"; "a faithful friend"; "fast friends"; "a loyal companion"; "she proved a true friend"; "a lover absolutely true in act and word and thought"- H.O.Taylor
4
devoted(p)
(followed by `to') dedicated exclusively to a purpose or use; "large sums devoted to the care of the poor"; "a life devoted to poetry"