Easy

I’d build a time machine, and use it to go back in time. So I could explain to Fred Trump, the importance of using a condom.

I’m sure I could find plenty of other things to do with a time machine too.

I hope my answer demonstrates the absurdity of this question. As a verified adventure junkie, I can attest to the fact, that there is no adventure in “Guaranteed not to fail.”

Daily writing prompt
What’s something you would attempt if you were guaranteed not to fail.