The Landlady - S3.E6

The rent is due for Raj and Rerun's apartment but they are short since Raj hasn't been able to find a job. When the landlady stops by to collect the rent she takes Raj aside and tells him not to worry and then proceeds to give Raj signals that convince him that she's interested in him romantically. Raj soon begins acting more mature since she's in her 30's and he's 19.