Bella Swan and Jacob Black

Bella and Jacob's relationship varies throughout the series, from friendship to love, love triangle, and eventually friendship again.

Twilight
In Twilight, Bella only encounters Jacob three times after she moved to Forks.

She first meets him on First Beach on La Push where she successfully flirts with him to gather information about the Quileute tribe's legends regarding vampires. He tells her what he knows about the Cold Ones and how the story relates to the Cullen family. Though her flirt was a trick to gather information, she express liking in Jacob and would like to hang out with him again.

The second time, Jacob visits Bella with his father. Billy warns Bella to stay away from Edward Cullen while sending Jacob away.

The third time, Billy sends Jacob to Forks High School on prom night to try and persuade her to break up with Edward, quoting we'll be watching over you. Jacob crashes the prom and dances with Bella before Edward takes over again, much to his dismay.

New Moon
Bella and Jacob ceased to meet since prom night. Months after Edward left Forks, Bella comes to find Jacob and persuades him to help her rebuild two dead motorcycles to experience adrenaline rushes in order to hear Edward's voice in her mind.

Eclipse
Their relationship wavers again in Eclipse.

Breaking Dawn
By the end of Breaking Dawn, they are finally able to put their issues behind them and become best friends once again.