Mitt Romney's wife, Ann, has painted a loving portrait of her husband at the Republican convention, on the day he became the party's White House nominee.
In her prime-time speech, Mrs Romney spoke of her "real marriage" to a steadfast, caring husband and father.
Correspondents say the address was an attempt to show the human side of the Republican, who lags behind President Barack Obama in likeability ratings.
Mr Romney will challenge the Democratic president in November's elections.
Opinion polls show Mr Romney neck and neck with the Democratic president.
Many voters have said the former Massachusetts governor and business star is still something of an unknown quantity.
'A better place'
Mrs Romney, 63, took to the stage after speeches from prominent Republicans, including South Carolina Governor Nikki Haley and former presidential candidate Rick Santorum.
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Telling the audience she wanted to "talk to you from my heart about our hearts", Mrs Romney said of her husband, "you really should get to know him".
She talked about the way her husband helped her deal with multiple sclerosis and breast cancer.
"I read somewhere that Mitt and I have a 'storybook marriage,'" she said.
"Well, in the storybooks I read, there were never long, long rainy winter afternoons in a house with five boys screaming at once. And those storybooks never seemed to have chapters on MS [multiple sclerosis] or breast cancer.
"A storybook marriage? No, not at all. What Mitt Romney and I have is a real marriage."
She added that her husband, who has not spoken much in public about his faith or private life, "doesn't like to talk about how he has helped others because he sees it as a privilege, not a political talking point".
Mrs Romney ended by pledging: "This man will not fail. This man will not let us down.
"He will take us to a better place, just as he took me home safely from that dance."
Mr Romney appeared on stage and kissed his wife as she concluded her remarks, to a standing ovation from the audience.
New Jersey Governor Chris Christie delivered the keynote address after Mrs Romney.
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The speeches followed a roll-call of party delegates and a lively voice poll in which state delegates called out their team's allocation of votes.
Altogether, Mr Romney secured 2,061 votes, bringing him up to the crucial 1,144 delegates needed to put him "over the top".
While Mr Romney was not present during the vote count, Mrs Romney confirmed that he would attend her address.
Vice-presidential candidate Paul Ryan was also given the Republican party's official stamp of approval on Tuesday.
During the Tuesday sessions, speakers attacked Mr Obama, with House Speaker John Boehner saying "his record is as shallow as his rhetoric".
Republican National Committee chairman Reince Priebus said the president has "never run a company. He hasn't even run a garage sale or seen the inside of a lemonade stand."
Abortion and Wall Street
The convention also approved its party platform - a policy agenda that calls for tax cuts to revive the economy, repealing and replacing a healthcare law passed by Mr Obama, and an end to abortion.
Recent opinion polls have indicated that voters view the economy and unemployment, which is stuck at 8.3%, as top priorities.
The platform also calls for the overturning of measures passed to regulate Wall Street in the wake of the 2008 economic collapse.
On abortion, the platform says: "The unborn child has a fundamental individual right to life which cannot be infringed."
That is more conservative than Mr Romney's declared view - he says he opposes abortions, except in cases of rape, incest, or when the mother's health is in danger.
This is Mr Romney's second run for the White House, after an unsuccessful bid in 2008.
President Obama's renomination will be confirmed next week at the Democratic National Convention in Charlotte, North Carolina.
This year's convention got off to a late start when Monday's programme was postponed amid concerns that Hurricane Isaac might disrupt the proceedings in Tampa.
But the category one hurricane missed Tampa, instead making landfall in southern Louisiana on Tuesday evening.
It comes almost seven years to the day since Hurricane Katrina devastated New Orleans.