Travel expenses for a job interview

i have been offered a job interview in Frankfurt, but the company says it will give me back my travel expenses. I was on one interview already, and the first company just booked me a ticket. This one leaves it to me. Do i have any guarantee that they will give me back travel expenses? i mean flight ticket is pretty expensive, i wouldn't come to them if they not cover it. They say they will... What if they don't? is there any way i can have guarantee that they will give me back travel expenses?

Read this ... if you understand German

In short, they have to pay for it. Go to the interview, you'll get your money back.

Most german companies are ok in this respect so long as you do not go overboard

They are required by law to pay your "reasonable" travel expenses. This usually means at least rail + taxi from the train station, if it's a longer ride (let's say from munich to berlin) a flight ticket is also covered.

So if they already said they will pay for the flight, they probably will It's pretty much standard.