A significant theme from the book "Only the Heart" is about identity and struggle. The quote "It is only though adversity that we become aware of our own strengths and become aware of our identity" relates to the characters in many ways. This includes the constant loss of family ties for the characters of the book and the grief that they experienced from running away from Vietnam and leaving everything they knew. .
Minh, Toan's father, gave up the chance to escape Vietnam before the fall of Saigon and instead choose to stay with his family and face whatever danger came to him. In this section of the book, he shows his strength and faith in his family. Before the boat departed, Minh left and went back to his family. He later tells his son " imagining what it would be like if I was safe somewhere and my family was still here" (p15). Minh realises that it is not right to desert his family during the dangerous time of the invasion of Saigon. In Vietnamese culture, the father usually holds the family together. Minh was brave and stayed to support his family for as long as he could.
Linh is one of the characters that is faced with the most testing adversity through out the whole book. She endures the most seeing violence and suffering happen to family and friends. She loses her father due then her mother because of pirates. Only being left with Phuong as a close family member, she sees her badly burnt because of fire on Pula Bisa. In Australia was in a car crash as a result, leaving her in a wheelchair for the rest of her life. Tang is then killed in front of her. After contemplating life she learns that "you grow out of everything either you let it destroy you or get on with what is left of your life" (p201). Linh secluded herself after the accident but started to recover after talks with family and friends. At the end of the book, Linh's character is almost revealed. She is a strong and determined woman keen to make the most out of her life and to help others make the most out of theirs.