Being safe online is important. To know if your email is coming from a secure sender the key is using a good email provider. My favorite email service is Gmail from Google. They provide great spam detection, verification (for paypal & ebay), priority inbox (filters important email from subscriptions etc.), and tons of extra custom settings.
Never send important information to others requesting it online. This is the safest way to protect yourself from getting taken by fraudulent emails. If you don’t know the person, don’t send them anything important (including birthdays, etc.).