Questions & Answers about Láska je důležitá.
Because láska is a feminine singular noun, and the adjective has to agree with it.
- láska = feminine singular
- důležitá = feminine singular form of důležitý = important
So Czech is doing something English does not usually show clearly: the adjective changes form to match the noun.
Other forms would be:
- důležitý = masculine singular
- důležitá = feminine singular
- důležité = neuter singular / some plural uses
In this sentence, důležitá matches láska.
Je is the 3rd person singular present tense of být, which means to be.
So:
- já jsem = I am
- ty jsi = you are
- on / ona / ono je = he / she / it is
In Láska je důležitá, je means is.