have a soft spot for or an animal

have a soft spot for (someone or something)

To have a particular fondness or affection for someone or something, often for reasons that hard to understand or articulate. I've always had a soft spot for cheesy action films—there's just an earnest goofiness about them that I like. Despite how troublesome he could be, the teacher had a soft spot for Daniel.
See also: have, soft, spot
Farlex Dictionary of Idioms.

have a soft spot (in one's heart) for someone or an animal

Fig. to have a fondness for someone, something, or an animal. I have a soft spot in my heart for Jeff. I'll always be his friend. Elaine has a soft spot for kittens.
See also: animal, have, soft, spot
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • have a soft spot for
  • have a soft spot for (someone or something)
  • have a soft spot for somebody/something
  • have a soft spot for someone/something
  • soft spot
  • a soft spot
  • take a liking to (someone or something)
  • take a fancy to
  • take a fancy to (someone or something)
  • take a fancy to somebody/something