My mother used to say “Even whores say no [sometimes].” She meant: If people who are considered by society the lowest of the low still say no sometimes, moreover you can.
My friend and teacher Harvey Jackins used to say: Learn to say no as if you hand someone the moon. As a great present. Not sternly.
To make our “no” clear, we sometimes need to state it over and over.
If one wants to be assertive without inherent violence, do so friendly and subjectively. I don’t want to. I don’t want to. I don’t see a way. Not semi-objectively (authoritarian): It is impossible.
Marshall Rosenberg taught me that not the tone of no indicates if it is violent but the consequence. Someone who would respect your no might ask for your answer fairly crudely. While some super-polite people may explode when you disagree.
We don’t need to regard no as a rejection of ourselves and not even of our request. No always means: no for now. Any no almost always can be an invitation to start negotiating.
The Jewish Prayerbook says every morning to humble us that the difference between people and animals is naught. However, this Hebrew can also be understood differently: that the difference between people and animals is that we can say no [to enticement]. Strong is someone who conquers his desire (Sayings of the Fathers 4:1).
The Hebrew Bible teaches us that the father who refuses to hit his son hates him. The intention is not to hit him physically, to be angry or violent with him. Rather, it means: if you love him, you must sometimes set limits. (To make it easier, you can invite your children and students also to set you limits. Meaning: I say no and must be heeded but not because I’m big and bossy – I too fall under G^d and am commanded.)
More than we feel loved for getting presents, we feel that someone is concerned about us when they care enough to tell us no, for our good.
A child (or grownup) spoiled rotten is not someone who has a lot, and especially not who is loved a lot, but rather, one who never hears no.
You can make your limit easier to take if you instead give options: Do you want to go to bed now or in five minutes?
You can say: You now must do as I tell you but soon we can talk about it. Make sure you keep your promise, and give empathy (Exodus 24:7: we will do and we will listen). Talking of which: sometimes we must stop arguing and first do something in order to understand the value of it.
A proper spouse is a helpmate opposite of you. That means: when you need support s/he will give you support; when you need opposition s/he will give you opposition. If s/he loves you, s/he can do so because it’s good for you, not for selfish reasons.
G^d want us to oppose Him when bad things are happening or about to happen. Not only can we say no to anything G^d did, does or will do – we are expected to do so to show that we want to join Him in good things and not destructive ones. (If G^d does it anyway, it means that for the greater picture it was needed, but also then, our opposition is virtuous.)
If there’s no legal and kosher way to get something, it means that G^d doesn’t want us to have it; and that having it would not be good for us. Unless G^d would want us to push for a change in the law.