In a futile effort to shift the burden of proof, and establish their claim "there is no God" as the logical default position, atheists often tell us that you can't prove a negative. The first problem with this, of course, is that "there is no God" is still a claim. The inability to prove it does not mean it is less necessary to try. Of course, if you wish to soften your statement to "I don't know if there is a God", that shifts the burden of proof. Which is absolutely fine. There is plenty of evidence that yes, there is a God, and yes, He is the God of the Bible. In fact, the evidence is so strong that it was sufficient to convince multiple stubborn atheists, even many who set out to disprove Christianity, to instead swallow their pride and lay their sins at the foot of the cross. Suffice to say, a faith so well evidenced as to do that is more than capable of meeting the challenge of agnosticism.
But if you maintain your claim that "there is no God", and if we ignore the fact that you are still required to prove that claim, it's actually not true that you can't prove a negative. In fact, due to the existence of the second law of logic, it's actually very easy to do.
The logical law of non contradiction states that two opposing truths cannot be true at the same time and in the same sense. For example, you cannot have a round square, but you can have a rounded square, or make a square round. Round and square are opposed to each other. If an object is square, it cannot be round. If an object is round, it cannot be square. However, depending on how liberal you are with your definitions, you can round off the corners from a square and call it a rounded square, such as in the image to the right of this paragraph. This is a "round square", because it is not round in the same sense as the circle. It is not even fully round. To make it round would be to make it a circle. Which you could technically do with the same shape, making it once again consistent, because it is not round and square at the same time. It was a square, but now it is round.
The way to prove a negative, therefore, is to provide positive evidence that would contradict your negative's antithesis. For example, Christianity stands or falls on the historical, bodily resurrection of Jesus. If Jesus did not rise, Christianity is not true. So, we have a host of possible negative statements to assess. Jesus did not exist, Jesus was not crucified, Jesus did not rise.
The first two statements are historically destitute. Of course, I would argue that all three are, but even atheistic historians, such as Bart Ehrman, would agree that yes, Jesus did live, and really was crucified. In fact, most laughably, he believes that Christians made up the whole resurrection narrative specifically to explain why Jesus was crucified. (1) Ehrman correctly points out that if Christians had made Jesus up, Him being crucified is about the last thing they'd invent. They'd have made Him a conqueror who took over Jerusalem. But of course, they couldn't do that, because there's a little problem called "culture". The people in Jesus' day knew full well who their rulers were, and of course they knew full well Jesus was crucified. It was a very public event.
So let's just focus on the disputed claim. Did Jesus rise, or did He stay dead? The statement "Jesus did not rise" could have been immediately proven with the production of His body. Obviously, that's an unreasonable thing to ask for today. But what about 2,000 years ago, when Jesus' body was highly valuable? Back then, it should have been easy to produce. When Jesus died, the Jews remembered how Jesus had predicted not only His death, but also His resurrection, so they guarded His tomb, lest "the last error shall be worse than the first." (Matthew 27:64). Why, then, given the strength of Jesus' body's transmission, did they not lay Him on a cart and parade it around the streets, immediately finishing all possible claims of resurrection?
With at least two groups, consisting of numerous powerful people, being highly motivated to produce a body they kept very tight possession of, the most reasonable explanation for Jesus' mysterious disappearance (not to mention appearance to His deserting Apostles, unbelieving brother, large crowds of people, and finally to an aggressively Church-persecuting Jew) is that the negative statement "Jesus did not rise" is actually false. Those who claim "Jesus did not rise" had their chance to prove their negative, but in spite of all their power, they failed miserably to do so. Even today, 2000 years later, when it is unreasonable to say "then produce the body of Jesus", it is still reasonable to ask for an alternative explanation of the facts which have yet to perish. With the minimum facts acknowledged even by sceptical scholars, it really seems like the central miracle of Christianity is a historical fact. Those who deny it have to come up with a myriad of strange stories, up to and including "Jesus had a secret twin brother", to explain the facts. This, to me, just doesn't seem reasonable. You decide if it seems reasonable to you.
References
1. Ehrman, Bart - Bart Ehrman Destroys Islam in 3 Minutes, Apostate Prophet, November 25th 2021 (link)