When speaking in French, a more polite way to express 'you're welcome' is actually 'Je vous remercie'. This phrase conveys gratitude and politeness. To say it with sincerity, you can add Cordialement before Je vous remercie, which means "with pleasure" or "in a friendly manner." For example, if someone thanks you for something, you could respond with: "Cordialement, je vous remercie". This response shows appreciation and friendliness, making it a more natural and polite way to acknowledge someone's gratitude in French.