Breakdown of Sú sem getur huggað hana best er systir hennar.
Questions & Answers about Sú sem getur huggað hana best er systir hennar.
Because sú is feminine singular.
Icelandic often matches this kind of pronoun to the gender of the person being referred to:
- sá sem = the one who (masculine)
- sú sem = the one who (feminine)
- það sem = that which / what (neuter, often for things or abstract reference)
Here the person is female, and the later phrase systir hennar also confirms that.