The word מעניינת inflects as a verb, because it's a present participle (which doubles as present tense verb and vice versa).
why the last word is for female ?
Because "career" is feminine in Hebrew
“He has an interesting career.”
Suggested as an“other” correct solution: “He has an interesting career.”
Wow! That’s as interesting as his career!
Yesh lo karyerah meanyenet.