Japanese people are really kind.
This product has gotten truly expensive.
Is this really the way?
本当 is reality or truth (level 5 vocab). If you go towards truth and reality, you are saying that it is really and truly true. 本当に! It is!
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well. It shares the reading with the level 5 本当 as well, but just has a particle on the end to show you're going towards reality. Really!