What programme can I use to convert a 3mf file to STL on Mac?

I hope that someone can recommend a programme to convert a 3mf file into an STL on a Mac?

For reference, on the course I was taking we were told to repair/fix Mesh for printing in Microsoft 3D Tools (as I have an account and it’s an online service I have no problems using this.) However, this makes it a 3mf file. On the course we were told to use 3D Builder to convert it back to a STL file but this is a Microsoft app and not available on Mac. Is there a Mac equivalent to 3D Builder? I’ve had a look around and seen Meshmixer. Will that work and is it safe to use? I do not want to download random software from the web. Thanks

Hello - Rhino should be able to open the 3mf and can write STL files…

-Pascal

Thanks @pascal Maybe be I should have tried that first but assumed we had to use another programme! Many thanks for your reply.