You sound like some holocaust deniers I once tried to debate. "Prove it," they said. And when I cited some evidence they said, "we don't believe it, that's not proof, the holocaust never happened and the Jews are evil!"
Naturally, since I'm not that bright, I tried again, and then again, always with the same results. Finally it began to dawn on me, these guys are not going to be convinced no matter what I say.
In the case of evolution: it's a scientific theory based on evidence, both the fossil record and living evidence such as Darwin found in the Galapagos Islands.
In recent years, evolution has been hugely supported by DNA analysis. Consider:
Identical twins have identical DNA.
People from the same families and tribes have very similar DNAs.
Human races can be distinguished by certain DNA differences.
Human DNA can be distinguished from chimpanzees by something like 5% of DNA differences.
Every species has similarities and differences in DNA from every other species. These differences correspond almost exactly to what is established by evolutionary theories.
In other words, where where the fossil record shows a common ancestor many millions of years ago, DNA analysis also shows a common ancestor many millions of years ago.
Or DNA shows that God used a limited number of building blocks. Simplicity and elegance of design.
Maybe some simple questions would suffice:
How old is the earth?
And how would you go about determining how old it is?
When you say ‘theory of evolution’, what does it mean to you?
Do you agree that some species that existed on earth are no longer here?
Do you agree that some places in mountains were once under water?