To effectively convey your serious love to your girlfriend, it's important to communicate your feelings and actions consistently. Here are a few steps to help you:

1. Express your feelings: Take the time to truly understand and articulate your love for her. Write down your thoughts or even practice saying them out loud before talking to her. Be genuine and specific about what you love about her and why she means so much to you.

2. Plan meaningful gestures: Show your love through actions that demonstrate your commitment and thoughtfulness. Plan special dates, surprise her with small gifts or gestures of affection, and ensure you're attentive to her needs and desires. These actions will convey your sincerity and the effort you put into loving her.

3. Effective communication: Express your love verbally by telling her regularly, both in words and tone, how much she means to you. Use "I" statements to avoid sounding accusatory – for example, instead of saying, "You never show me you love me," say, "I feel loved when you..." This approach helps open up a constructive dialog without causing defensiveness.

4. Quality time: Dedicate quality time exclusively for the two of you to strengthen your connection. Engage in activities that you both enjoy, listen actively, and engage in meaningful conversation. Being present in the moment and fully focused on her will demonstrate your commitment and love.

5. Acknowledge her love language: Everyone has different ways of feeling loved. Understanding your girlfriend's love language can be helpful in tailoring your efforts accordingly. Whether it's acts of service, quality time, physical touch, words of affirmation, or receiving gifts, make an effort to show love in ways that resonate with her specifically.

6. Be patient and consistent: Building trust and deepening love takes time. Be patient if your girlfriend needs time to fully realize and reciprocate your love. Consistently showing love and devotion will help solidify your connection over time.

Remember, actions often speak louder than words. Continuously showing love and commitment through your actions, in addition to expressing your feelings, will help communicate the depth of your love to your girlfriend. Be open, honest, and patient throughout the process, and stay true to your intentions.