This is the 16552nd most frequent Korean word.
사람이지만
"사람이지만" means "although (I am/they are) a person" in English.
The word '사람이지만' here compounds '사람' (person) with '이지만' (but) to contrast qualities, specifically her kindness versus her strictness.
그녀는 천사 같은 사람이지만 때로는 좀 엄격해요.
She is an angel-like person, but sometimes she is a bit strict.
The usage of '사람이지만' contrasts his busy nature with his effort to make time.
그는 매우 바쁜 사람이지만 항상 시간을 내줘요.
He is a very busy person but always makes time.
'사람이지만' illustrates the nature of being human while introducing imperfection.