WordNet sense 1 (a warmhearted feeling):

warmheartedness

WordNet sense 2 (the sensation caused by heat energy):

heat

WordNet sense 3 (the quality of having a moderate degree of heat):

warmness

WordNet sense 4 (the trait of being intensely emotional):

passion

WordNet sense 5 (a quality proceeding from feelings of affection or love):

fondness, affectionateness, lovingness