c. 1400, originally in reference to the presence of Christ in the Eucharist, from real (adj.) + -ly (2). Sense of "actually" is from early 15c. Purely emphatic use dates from c. 1600; interrogative use (oh, really?) is first recorded 1815.
they don't really listen to us
really, you shouldn't have done it
a really enjoyable evening
realization
realize
re-allocate
re-allocation
re-ally
really
realm
realpolitik
Realtor
realty
ream