From Longman Dictionary of Contemporary Englishopen your heart (to somebody)open your heart (to somebody)TRUSTto tell someone your real thoughts and feelings because you trust them → open
Examples from the Corpus
open your heart (to somebody)• She thought about it and decided it was a sign, and what it meant was: open your heart.• Robbie opened his heart after a secret charity gig at London's Equinox club on Thursday.• Just allow your intuitive faculties to operate, open your heart and be honest with yourself and the landscape.• We opened our hearts and wept.• For her part, she felt that he was some one to whom she could open her heart and who would understand.• He was close to tears when he started to read a statement in which he opened his heart as never before.• Three quarters of all the teenagers questioned would open their hearts at home. 