CP will be my answer as you can sit in the park to talk and for eating there is cha bar and shake square(my favourite because of the decor and there shakes are best).
You can also go to Cantino in GTB Nagar, affordable and really very good food and you can go shopping too to kamla nagar which is very near.
Head to Sunder Nursery and then a boat ride at the old fort lake. Followed by lunch at Cafe Lota and browsing around the crafts museum. End with a chuski at India Gate.
Cannought place would be a good option
Right now Box park is going on at DLF promenade. Great food n ambience. And gr8 shopping options
Check out Smaaash (has a few outlets across Delhi NCR) for a fun date where you can play arcade games, there's bowling🎳 etc. and you can eat & drink too.
You can have a fun and affordable date at the trampoline park (greater Noida )
Venice mall gr.noida provides boat ride to give a Venice city feel, then there is ziplining and moreover there's trampoline park, snow park and what not. Must visit for fun date. There's also EOD Adventure park in Mayur vihar for fun affordable date. Rate there is pretty casual.