What are the good ways to say NO?

I can't fully dedicate myself to... so I must say no.

Politely say no, you may also show better options so that the other person himself switch to other ways and take back his request:)

Simply say No and a true reason It will save you both time.

Be yourself. No need to justify your intentions.

Directly say NO. If someone is very close to you, tell them the reason and they will understand.

It Depends On What The Situation Is.
The Best Thing To Do Is Just Be Firm And Say No, Because If You Leave Any Doubt As To What Your Decision Is, Then The Person Will Continue To Make The Same Request With The Expectation That Your Answer Will Someday Be Yes.

No need to satisfy them "Just say No" If you want

Say NO and explain why. They will appreciate it and will search for help from others. If you say YES not to offend them and fail to be of help, you will both be disappointed.

but if the person doesn't know you and is asking you for something you don't normally do or give, I'd simply let the person know that you are uncomfortable with the request and will have to decline it.

Directly say NO. If someone is very close to you, tell them will let you know in sometime.

When you say "Someone is expecting something from you but you cannot fulfill," I think it depends on the expectation. If this person expecting something from you knows that you are usually helpful and giving then saying "no" should be quite easy. But if the person doesn't know you and is asking you for something you don't normally do or give, I'd simply let the person know that you are uncomfortable with the request and will have to decline it.

There are many ways to say No. One of them is Say " I am little bit busy right now, Will talk to you later about that matter".

Simply say No and a true reason
It will save you both time.

Identify what’s important to you and acknowledge what’s not and choose some easy, low-risk situations in which to practice saying no.that help you boost your confidence in saying no.

Politely say no, you may also show better options so that the other person himself switch to other ways and take back his request:)

Sorry, I'm booked into something else right now.
Sadly, I have something else.
No, thank you but it sounds lovely, so next time.
I'm not taking anything else right now.

say no without saying No.. i mean you can say you already have it so thanks i will let you know if i need again

just be polite and say NO

It is important to be straightforward and firm when you state your boundaries. Don't be afraid to tell people no.

I'm honored but I can't.