Plz, check expirations below
Sara loved to read
is grammatically correct but would it be incorrect if we say it
sara loved reading
read in first expiration is verb I think but secound one is noun obviously
In this case both are acceptable.
The word "reading" can be understood as a noun, but most people would call it a "gerund" as it could take an object "Sara likes reading the newspaper"
In general some situations require an infinitive, some require a gerund, and in others both are acceptable.