"If the relationship doesn't make you a better person" implies that a significant aspect of a successful partnership is its potential to inspire growth and positive change in both individuals involved.
"Then you are with the wrong one" suggests that if a relationship hinders personal development, it may not be the right fit. It encourages individuals to assess whether their partnership aligns with their goals and values.
In essence, this quote underscores the importance of mutual growth and self-improvement within a relationship. It suggests that being with a partner who supports and encourages personal development can lead to a more fulfilling and meaningful connection.