James 1 says, “If any of you lacks wisdom, let them request it from God, from the one who gives generously to all, and who doesn’t reproach — and it’ll be given to them.”

So that’s guaranteed?
James goes on to add, “And let them request it in faith, without doubting anything, for the one who doubts resembles a wave of the sea, which is driven and tossed by the wind. For don’t let that person suppose that they’ll receive anything from the lord.”

So you/we will only receive it if we have faith. If we are already certain when we pray, that we will receive it.

Otherwise, we’re just “hoping”, and James says, we won’t receive anything.
I would say that sometimes Yahweh is gracious and merciful, and does give it to us anyway.
But that’s not what we’re talking about here. We’re talking about knowing when you pray, that your prayer will be answered as you asked.

There is one misconception that we should clear up first.
Why should Yahweh answer your prayer?
And what possible chance do you have of him doing that if you’ve been sinning all day?

I honestly don’t see this taught in many places… but even if you have been sinning all day, if your prayer is based on the name of Yeshua, then you still have a 100% guarantee that it will be answered.
And it doesn’t go the other way either, so you can’t be good for long enough to clock up enough points with God that “you are now entitled to one answered prayer”. It just doesn’t work that way.
Because it’s never answered based on your behaviour, (good or bad), it’s only ever answered based on Yeshua’s sacrifice.

When you become a Christian, Yeshua’s sacrifice is counted as the full atonement for your sins. So when Yahweh looks down on you from then on, he looks down and sees “sinless”. This is how “in the name of Yeshua” works. It’s not a magic phrase which unlocks the power of the universe. It’s not that if you forget to add that tag line at the end of your prayer it won’t work.
It’s that in your heart you know that the only way you dare come before Yahweh is because to him you are sinless because of the sacrifice of Yeshua.

But, does that mean that Yahweh will give you anything you pray for?
Well, kinda, but kinda not.
A new car? A million dollars? Your cancer cured? Your child back from the dead? Live to be 150 years old?

It depends on whether that fits in with his own agenda… So first, you need to have a chat with him about his agenda, and whether it does or not.

Sometimes he will. Even those way out there things.
I’ve seen quite a few miraculous healings. But I still don’t always pray for that without asking first. And when I do ask, sometimes it’s pretty clear that the answer will be “no”. So I pray for another outcome, like peace for the person, or their family.

I’ve seen a group of men praying for their mission which is in financial trouble, but which they are sure that Yahweh wants to continue. One of the men stood up and prayed, “Lord, it says in Psalm 50 that the cattle on a thousand hills are yours. Please sell some of them so we can continue this ministry.”… Knock, knock, … there was someone at the door.
In came a man from their church. “I’ve just sold my farm for millions of dollars. I want to buy each of you a house so you can stop worrying about money, and I want to fund your ministry.”

Just praying for the best outcome, the one you want for whatever reason, isn’t Biblical prayer. It’s worldly prayer. Just like all those religions to false gods out there, where they go to the temple, and try to do some ritual or offering, in the hope that they will get what they ask for. And if they don’t get it, they assume they did something wrong when they did the ritual.

Prayer should glorify God when he answers. Especially the big ones. And of course he would be glorified if someone is miraculously healed by a prayer to him… But how would the world react if every prayer “in Yeshua’s name” was answered?
Remember that Jim Carey movie, where he had to do God’s job for a while, and to respond to every prayer. And there were so many he just hit “yes” to all of them. Chaos.

Why should God answer your prayer? What’s in it for him? How does it fit with his big picture agenda?
What is he saying back to you when you ask him about this?
Do you feel like, “He’s not going to do it? So I shouldn’t ask”. Or do you feel like, “He really is going to do it. I should definitely pray”.

Pray based on that answer. Whether you want that outcome or not.
And then what Yeshua said will be true for you, “Whatever you request, praying, trust that you receive, and it will be so for you.”