由衷

yóuzhōng
  1. heartfelt
  2. sincere
  3. unfeigned

CEDICT

Entry Composition

1 由 yóu
  1. to follow
  2. from
  3. because of; due to
  4. by; via; through
  5. (before a noun and a verb) it is for ... to ...
2 衷 zhōng inner feelings