To endure means to suffer for an extended period of time with patience.

To use endure in a sentence, "The wounded solider will have to endure a lot of rehab to walk again."

To think about something means to ponder.

To use ponder in a sentence, "High school seniors usually ponder about which college to attend."

Something that is authentic is real, or original.

To use authentic in a sentence, "The family ate at an authentic Mexican restaurant downtown."