German phrase
Ich möchte ~ anprobieren.
Meaning
I'd like to try on ___
When to use it
It asks to try something on. Natural and polite in a clothing shop.
Example dialogue
Ich möchte dieses Kleid anprobieren.
I'd like to try on this dress.
Gern, welche Größe darf es sein?
Certainly, what size would you like?