Sentir vs. sentirse

The Spanish verbs 'sentir' and 'sentirse' both translate to 'to feel' in English but are used in slightly different contexts.

Sentir

The verb 'sentir' is a transitive verb that requires a direct object. It is used to express physical sensations or emotions that someone feels towards something or someone.
Siento frío.
(I feel cold.)
Sentimos mucha alegría al verte.
(We feel a lot of joy seeing you.)
¿Sientes dolor en el brazo?
(Do you feel pain in your arm?)
Ella siente tristeza por la noticia.
(She feels sadness about the news.)

Sentirse

'Sentirse' is a reflexive verb, meaning it reflects back to the subject. It is often used to describe the subject's internal state or how they perceive their own feelings or physical condition.
Me siento bien hoy.
(I feel good today.)
Nos sentimos cansados después de trabajar.
(We feel tired after working.)
¿Te sientes mejor?
(Do you feel better?)
Él se siente feliz con su nuevo trabajo.
(He feels happy with their new job.)

Summary

'Sentir' and 'sentirse' both mean 'to feel', but they are used differently. 'Sentir' is a transitive verb requiring a direct object and expresses feelings towards external things, while 'sentirse' is reflexive and describes one's internal emotional or physical state.