When a woman with a childish mentality falls in love with you, there may be certain signs or behaviors she displays that indicate her feelings. Here are a few common signs:

1. Playfulness and carefree nature: A woman with a childish mentality may become more playful and carefree around you. She may engage in unpredictable and lighthearted activities, showing her excitement and willingness to have fun together.

2. Need for attention and validation: As she falls in love, she may seek more attention and validation from you. This can manifest in various ways, such as constantly seeking your approval or seeking reassurance about your feelings for her.

3. Emotional vulnerability: In a childlike manner, she might express her emotions more openly and without inhibition. She may be more prone to display happiness, sadness, or even frustration, allowing her emotions to surface without holding back.

4. Idealization and admiration: When she develops feelings for you, she may idealize your qualities and put you on a pedestal. She may express admiration for your achievements, skills, or even your physical appearance, sometimes in an exaggerated way.

5. Eagerness to please: A woman with a childish mentality might go above and beyond to please you. She may try to make you happy by doing small acts of kindness or going out of her way to fulfill your desires, expecting appreciation in return.

6. Jealousy and possessiveness: While it's not exclusive to a childish mentality, she may display signs of jealousy or possessiveness. Her fear of losing your attention or affection might make her act out or become overly protective.

Remember, everyone is unique, and these signs may not apply to every woman with a childish mentality. It is important to communicate openly with your partner and understand her specific needs and behaviors in the context of your relationship.