The primary meaning of -ért is, of course, "for a specific goal or cause" or "to get a specific item."
- Egy jobb világért harcolunk. = "We are fighting for a better world."
- Az őzet húsáért vadásszák. = "Deer are hunted for their meat."
- Lemegyek a boltba kenyérért. = "I am going down to the store to get some bread."
- Őt sem az eszéért szeretjük. - (something you would hear about someone who does something stupid) "It's not because he/she is smart that we like him/her."
To ask, use the interrogative pronoun miért?
-ért has a secondary meaning: "in exchange for..." (e.g. a specific amount)
- Ezt a könyvet húsz forintért vettem. = "I bought this book for twenty forints.
To ask, use the interrogative pronoun mennyiért?
If I had to make a sentence with barátságosságunkért, it would be:
- Ezt a barátságosságunkért cserébe kaptuk. = "We got this in exchange for our friendliness."
"A fiatal oroszlánok" here is a generalization, "[all] young lions are friendly," so "the" doesn't belong in the English version. But how would you express "the young lions" as a distinct group without using "azok"? For example, "The adult rabbits are vicious, but the young lions are friendly."