Devoted, a.
Consecrated to a purpose; strongly attached; zealous; devout; as, a devoted admirer. -- De*vot"ed*ly, adv. -- De*vot"ed*ness, n.
Shades of meaning
Fernald has no entry of its own for devoted; he lists it under addicted, faithful, holy.
Where he writes about it:
A man may be accustomed to labor, attached to his profession, devoted to his religion, given to study or to gluttony (in the bad sense, given over, or given up, is a stronger and more hopeless expression, as is abandoned). — from addicted
Devoted is used chiefly in the good sense; as, a mother's devoted affection. — from addicted
Affectionate, devoted, and tender are almost always used in a high and good sense; as, an affectionate son; a devoted friend; "the tender mercy of our God," Luke i, 78. — from friendly