How do I kindly let him/her know about that mood killing bad breath?

Question: How do I kindly let him/her know about that mood killing bad breath?

Answer: The kindest way to handle this is the most subtle, invest in breath spray or mints and before the two of you start kissing pop one yourself. Turn to your date and say, "I think fresh breath should be a kissing priority, don't you?" then give him/her a mint or hand over the breath spray. When you phrase it like this it doesn't allow for a "no thanks" response and is non-threatening since you freshened your breath as well.