The couple got engaged earlier this month.
A source exclusively tells ET that the 24-year-old singer has "never been so happy."
"Justin is in a really good place, and has been telling friends he's never felt more sure about a woman in his life," the source says. "Justin is head over heels in love with Hailey."
The source continues, "Justin and Hailey get along great, are on the same page about their faith and what they both want out of their future together. It took some time for Justin and Hailey to get back together, but the couple knows it was worth the wait."
Bieber -- who previously dated Selena Gomez -- popped the question to the bride-to-be earlier this month while on vacation in the Bahamas. "Justin and Hailey can't wait to be husband and wife," the source adds.
“[Hailey’s sister], Alaia, and [her cousin] Ireland, they’re in the wedding," Basinger -- who is the ex-wife of Hailey's uncle, Alec Baldwin, and the mother of her cousin, Ireland Baldwin -- told Us Weekly last week. "So, believe me… it’s cool!"
Just days ago, a source told ET that the couple's upcoming nuptials will not be too extravagant.
"Justin and Hailey have been telling friends they want to have a smaller wedding, with close family and friends, nothing too over the top," the source revealed. "The couple has discussed where they would have their wedding, in either Canada or somewhere in the States (NY or LA). They've thrown around the idea of having it in possibly both, but it's still the early stages of planning. Justin and Hailey are trying to enjoy the excitement of engagement before fully diving into wedding planning."
Here's more on the pair: