soeur is "sister" in French
To write "my sister" in French, you would say "ma soeur."
désolé ma chère soeur
"Ma soeur fait ses études au collège."
their sister -> leur sœur
ma belle sœur et nièce (only my sister is beautiful) mes belles sœur et nièce (they are both beautiful) note that "belle-sœur" in French sounds exactly the same, and means sister-in-law. A French speaker hearing this will certainly think of your sister in law.
"Sister" in French is "sœur."
"Sister" in French is "soeur."
A sister is "une soeur" in French. The plural is "des soeurs".
Sister Mariah is "Soeur Mariah" in French.
The French word for "your sister" is "ta sœur".
Sister
his sister = sa soeur. In French, the pronoun refers to the object of the sentence.