Je voudrais essayer cette robe dans une taille plus grande.

Pronunciation: zhuh voo-dreh eh-say-yay set rob dahn oon tye-yuh pluh grahnd.

Meaning: I would like to try on this dress in a larger size.

This polite phrase uses the conditional tense (voudrais) and is essential when shopping for clothing in French-speaking countries, where fitting rooms are common but you need to ask courteously.