cat test.txt | sed -n '/^start/,/^end/{/^start/,/i hate you/{/i hate you/p;};}'
i hate you 2
i hate you 4
i hate you 6
cat test.txt| awk '/start /{in_block=1; next} in_block && /i hate you/{t=$0; in_block=0; next} t && /end/{print t; t=""}'
i hate you 2