What is the conflict between Jess and Leslie in Chapter Seven?
The conflict is that Jess wants Leslie to come play in Terabithia with him, but Leslie is busy repairing the old house with her dad, Bill. Plus, Jess doesn't understand why Leslie wants to spend so much time with her dad, getting to know him, instead of playing with Jess, who's her own age. He thinks it's weird:
"It had never occurred to Jess that parents were meant to be understood any more than the safe at the Millsburg First National was sitting around begging him to crack it. Parents were what they were; it wasn't up to you to try to puzzle them out."
Of course, as readers, we understand that Jess is feeling both boredom and jealousy, and he's blaming it on Leslie and Bill. Here he is, focusing on how much he dislikes Bill and feels uncomfortable around him:
"Jess's feelings about Leslie's father poked up like a canker sore."
That is, Jess feels nettled by the whole situation and blames Bill for taking up Leslie's free time.
Finally, in February, Leslie and Jess talk it over. Jess realizes that he doesn't dislike Bill after all--he just hasn't gotten to know him yet, and Jess feels awkward about what to call him ("Mr. Burke"? "Bill"?)
It suddenly dawns on Jess, when Leslie suggests it, that the obvious solution to the conflict is for Jess to join Leslie and Bill on their project to repair the house. To Jess's credit, he realizes how dumb he's been acting:
"It was like all the lights coming back on after an electrical storm. Lord, who was the stupid one?"
Now he can spend time with his friend, not feel jealous, and not feel bored or stuck at home, either. He gets to know Bill better, too, and gets used to calling him by his first name. Plus, now the three of them are doing something productive together as well as learning new skills. You might argue that this activity is even better for the kids' friendship than playing in the woods in "Terabithia."