もっと長く

longer

→ もっと
phrase Rare #24,890
longer Often means “for longer” when referring to how long someone stays or does something.
JA: 今日はもっと長くここにいます。
EN: I’ll stay here longer today.

君への愛は空に星の輝く限りそれよりもっと長くそばにいたい

My love for you will last as long as the stars shine in the sky—and I want to stay by your side even longer.

— アバウト・タイム ~愛おしい時間について~ (2013)

次の時はもっと長くいるって約束するよ。

I promise I'll stay longer next time.

ここに、もっと長くいたい。

I want to stay here longer.