Many of us struggle to say no to expectations and requests of others even when we know that we don't have the time, interest or energy to fulfill them. It is perhaps why our lives often feel too busy and our energy too depleted. Yet without saying "no" to some things we cannot say "yes" to other more important things. Seen in this light, our "no" when necessary, is a positive and necessary word.
When we choose to say "no" we often feel as if we need to explain ourselves which indicates that we are feeling guilt over our decision. It is not necessary. "No" is a complete sentence which does not require us to explain why or to justify our decision. A gracious decline without explanation is a stronger answer than an explanation as to why we are saying no. If we feel an explanation is necessary, something like this suffices well:
"I appreciate the request. I regularly evaluate opportunities against those things that I know I am called to do and therefore need to graciously decline your request. Thank you for thinking of me."
While "no" is perceived as a negative word, it is actually a very positive word because it allows us the opportunity to do those things that are most important to us. No one accomplishes great things without saying no to many lesser things. It is a "boundary" word in our lives that indicates that the request is outside our present priorities. Therefore to say "yes" would be to violate our most important priorities. Seen in that light, "no" is a necessary and very positive word.