grep two strings but only if the 2nd string is in the next line

Question

I can grep two strings 'ion' and 'spin' from a file but would also like to either:

• grep only if both strings exist
• or only grep if the 2nd string is in the next line

grep -w 'ion\|spin' filename

I want to grep from a file which contains random strings like this:

  <set comment="ion 3">
   <set comment="spin 1">

but only if the word "spin" occurs in the next line.