Formal:
* J'espère vous revoir un jour. (I hope to see you again someday.)
* J'espère vous rencontrer un jour. (I hope to meet you someday.)
Informal:
* J'espère te revoir un jour. (I hope to see you again someday.)
* J'espère te rencontrer un jour. (I hope to meet you someday.)
* J'ai hâte de te revoir un jour. (I look forward to seeing you again someday.)
More poetic:
* J'espère que nos chemins se croiseront un jour. (I hope our paths will cross someday.)
Important Note:
* When using the formal "vous," you are addressing someone with respect, such as a person in a position of authority or someone you don't know well.
* When using the informal "tu," you are addressing someone you know well, like a friend or family member.
Choose the phrase that best fits the situation and the person you are talking to.