deep inside, in one's heart

I keep it.

私はしまっておきます

I keep the memories of the trip deep inside.

私は旅の思い出を心の内にしまっておきます

I keep the memories of the trip deep inside at home.

私は家で旅の思い出を心の内にしまっておきます

I keep the memories of the trip deep inside at home even after the trip is over.

私は旅行を終えた後も家で旅の思い出を心の内にしまっておきます

I keep the memories of the trip deep inside at home with my friend even after the trip is over.

私は旅行を終えた後も家で友達と一緒に旅の思い出を心の内にしまっておきます