伤心的时候也要对你笑一笑
[shāng xīn de shí hòu yĕ yào duì nĭ xiào yī xiào]
'When sad, still give you a smile' implies that no matter how sorrowful or painful it may be inside, the person chooses to put on a smile when facing someone special, showing care, politeness or uncomplaining support and company.