This usually refers to someone that doesn't express a feeling or opinion before something happens. They will suffer in silence when it's over because it will be too late.

It means to hold back your opinion or thoughts on something that you disagree about or makes you unhappy. For example if you liked a boy/girl but never told them because you're afraid of what they'll say you would be "suffering in silence" because you never expressed your feelings for that person.

saya kira artinya seperti seorang yang tidak mengekspressikan perasaanya jadi dia cuman bisa menyimpannya di dalam hati (menderita dalam diam)

if you do not have the courage to voice for yourself at the right time , you would be forced to accept a proposal which is not favorable to you . Then you would become a suffer in silence .