Nasza miłość będzie trwała wiecznie.

English Translation

Our love will last forever.

This sentence is in the future continuous tense formed using the structure:
To be in its future conjugation form + third-person Past Tense verb form thus
Być in its third person singular future conjugation form - Będzie
Third person singular feminine past tense verb form (to agree with the feminine noun “miłość”) - Trwała