You want her to say yes, but you don’t ask her to say yes because she might say no.
But if you do that, she can’t say yes, because you haven’t asked for it. So her answer defaults to no.
Thus, because you are frightened of her saying no, you decide she will effectively say no to you.
Thus unless you ask, you will never get a yes, and always get a no.
If you ask her to say yes, and she says no, nothing has changed as you were living without the yes anyway.
But if she says no, that makes you free to start looking for yes from a different woman.
Or she might say yes and then you have the yes that you want.
Your agonized wondering if she will say yes or no, does not actually alter her decision about her saying yes or no. So your mental turmoil serves no purpose apart from making you unhappy, unless you agonize for long enough that her yes if you had actually just asked her, turns into a no because you didn’t.
So if you ask and she says yes, you win because you have your yes. If you ask and she says no, you don’t actually lose anything, because you were already living the no anyway, and it allows you to seek a new woman to say yes.