熱心 (ねっしん) — enthusiastic, eager, devoted

熱ねっ心しん enthusiastic

Frequency #2667 Frequency rank among common Japanese words. Lower number = more common. Grade 4 Japanese school grade level in which this kanji is taught. Grade 1 is first year of elementary school. 2 characters 混合 mixed Mixed compound — combines different reading types in a pattern that doesn't fit the standard categories. na-adjective Part of speech (JMdict: adj-na, n)

nesshin

Pitch高低アクセント — Tokyo-dialect pitch accent. The number is the drop position: 0 = heiban (no drop), 1 = atamadaka (drops after 1st mora), N = drops after Nth mora. The line above each mora marks high pitch; below, low. ねっしん[1] atamadaka 頭高

Synth audio is approximate — the diagram is the canonical reference.