Honesty and loyalty are key. If two people can be honest with each other about everything, that's probably the biggest key to success.

This quote means that if two people are honest with each other and show loyalty, they are more likely to have a successful relationship. Honesty means being truthful and not hiding anything, while loyalty means being faithful and standing by each other. If two people are open and truthful with each other and stay committed and faithful to each other no matter what, then they are more likely to have a successful relationship.