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to melt into; to dissolve into; to merge into
to blend into (surroundings); to fit in; to adapt to; to integrate
砂糖がコーヒーに完全に融け込んだ。
The sugar completely dissolved into the coffee.
転校生がすぐにクラスに融け込んだ。
The transfer student quickly blended into the class.
雪が春の暖かさに融け込んでいった。
The snow gradually melted into the warmth of spring.