This is the 3815th most frequent Japanese word.
みせ
Shop; store.
Here, 'みせ' is used as a noun meaning 'store' or 'shop'.
このみせは大きいです。
This store is large.
In this sentence, 'みせ' is a form of the verb 'みせる', which means 'to show'.
あなたにみせたいものがあります。
I have something I want to show you.
Again, 'みせ' is a variation of 'みせる' here, used in a polite expression.