To swing, sway, or shake — physical movement back and forth or trembling.
吊り橋が風で揺らいでいるのを感じた。
I felt the suspension bridge swaying in the wind.
木の枝が揺らいで葉がカサカサと音を立てた。
The tree branches swayed and the leaves rustled.
船が波でゆっくり揺らいだ。
The boat slowly rocked on the waves.
To waver or become unsettled — one's mind, resolve, or a situation becomes unstable or shaken.
長年の信念が最近の出来事で揺らいだ。
My long-held beliefs were shaken by recent events.
景気の先行きが揺らいでいるため、投資家は慎重になった。
Because the economic outlook is unstable, investors became cautious.
彼女の約束が本当に守られるか、心が揺らぐ。
I'm unsure whether she'll really keep her promise; my mind is wavering.