Tonight Mitt Romney will have to speak to undecided voters — it’s something of a debut for him on the national stage — but he also needs to strengthen his relationship with his own party.

As I talked to delegates this week, they all are supportive and accepting, but not many are enthusiastic about their nominee. Sure, they’re excited about Paul Ryan. Yes, they desperately want to beat Barack Obama. But they are not bubbling over with energy for the presidential nominee himself.

First, I noticed that many Romney delegates weren’t even Romney backers in 2008 — I talked to a few who backed McCain or Huckabee that year. I got the sense that, even for his delegates, Romney represented “settling.” Kathrine Baxter of California called him “a steady hand on the wheel.” Other Romney delegates told me they backed him because he represented the best chance to beat Obama.

Alabama Santorum delegate Greg Waldrop said he has grown “comfortable” with Romney. Gingrich delegate Susan Witcher gushed about her candidate (“just brilliant”) and about Paul Ryan (“Love him… Wonderful!”) but all she could say for Romney was “through Ann, we’re getting to know Mitt.”

“I’m a little disappointed we had to settle for him,” Ron Paul delegate Ken Lucier of Minnesota told me.

So Mitt Romney has gotten the Republican base to agree to marriage. Tonight can he seal the deal?