Trierweiler, who went ahead with her India visit despite the weekend announcement of the separation by Hollande, said she was happy to be here for a "cause close to her heart".
"I am happy to be here. Don't be worried about me. I have time....Years to live," Trierweiler, 48, a career journalist and Hollande's partner of eight years, told a media conference organised for the launch of charity Fight Hunger Foundation.
A distraught Trierweiler was hospitalised for a week after the scandal became public and was later resting at a presidential retreat before embarking on visit to India.
"I was able to discover people who I hadn't known. I understood that you can be useful, and in being useful to others you can be useful to yourself," she said, speaking in French.
Trierweiler assumed responsibilities of the first lady after Hollande's election in 2012.
"This visit has been in my diary for the last six months and we have been planning it for the last year. I wouldn't have missed it for the world," she said, putting up a brave face.