No Muslim can marry a Hindu. But if a Hindu converts to Islam, he/she is no longer a Hindu but a Muslim so one could marry them. Same with any other religion. Apart from Jewish and Christian women who can still be married to a Muslim man without converting.
Deeba, there is unanimous consensus that a Muslim women can not marry any one other than a Muslim. A few ‘modern’ imams here and there who proclaim otherwise do not constitute ‘ikhtilaf’ or a ‘lot of controversy.’